На обед мы сделали салат с фасолью и кукурузой.

Yes, на often means on, but it has several common uses in Russian.

In На обед, the phrase means for lunch or as lunch. It is a very common expression:

• на завтрак = for breakfast
• на обед = for lunch
• на ужин = for dinner

So На обед мы сделали салат... means something like For lunch, we made a salad...

A useful thing to remember: after на with this meaning, Russian often uses the accusative case.

This is about aspect, which is very important in Russian verbs.

• делать / делали = imperfective
  Focuses on process, repetition, or an ongoing action.
• сделать / сделали = perfective
  Focuses on a completed result.

Here, сделали is used because the sentence is about a completed action: the salad got made.

So:

• Мы делали салат = We were making a salad / We made salad (with focus on the process, context-dependent)
• Мы сделали салат = We made a salad (finished result)

In this sentence, the speaker is simply stating what they prepared for lunch, so сделали is the natural choice.

Yes, literally сделать comes from the same verb family as делать, which often means to do, but in Russian it can also mean to make in many contexts.

So:

• делать домашнее задание = to do homework
• делать салат = to make a salad
• сделать салат = to make a salad, finish making it

This is normal Russian usage. English separates do and make more clearly than Russian does.

Yes, Russian can often omit subject pronouns when the verb already makes the subject clear.

• Сделали салат с фасолью и кукурузой.
  = (We) made a salad with beans and corn.
• Мы сделали салат с фасолью и кукурузой.
  = We made a salad with beans and corn.

Including мы can:

• add emphasis,
• make the sentence clearer,
• or simply sound more natural in context.

So both are possible, but мы is not required the way we usually is in English.

Because the preposition с meaning with normally requires the instrumental case.

So:

• фасоль → с фасолью
• кукуруза → с кукурузой

That is why both nouns change.

This is one of the first very common uses of the instrumental case:

• чай с сахаром = tea with sugar
• бутерброд с сыром = a sandwich with cheese
• салат с фасолью и кукурузой = salad with beans and corn

Both are singular instrumental forms.

фасоль

This is a feminine noun ending in a soft sign -ь.

Its instrumental singular ending is -ью:

• фасоль → фасолью

кукуруза

This is a feminine noun ending in -а.

Its instrumental singular ending is usually -ой:

• кукуруза → кукурузой

So the pattern is:

• feminine in -а → often -ой in instrumental singular
• feminine in soft sign -ь → often -ью in instrumental singular

Because Russian often treats foods like these as mass nouns, where English may prefer plurals.

So:

• фасоль = beans / bean as a food substance
• кукуруза = corn as a food substance

This is similar to how English says:

• rice
• milk
• bread

You would not normally pluralize them in this kind of sentence. Russian is focusing on the ingredient as a substance, not on countable individual beans or kernels.

It is accusative singular after на in the expression на обед.

For this noun, the accusative looks the same as the nominative:

• nominative: обед
• accusative: обед

So even though the form does not change, the case is still accusative because the phrase means for lunch.

Yes. Russian word order is flexible, and changing it can shift emphasis.

The original:

• На обед мы сделали салат с фасолью и кукурузой.

This puts На обед first, so the sentence starts with the context for lunch.

Other possible orders:

• Мы сделали на обед салат с фасолью и кукурузой.
• Салат с фасолью и кукурузой мы сделали на обед.

These all mean roughly the same thing, but the emphasis changes:

• sentence-initial На обед highlights the meal,
• sentence-initial Мы highlights who did it,
• sentence-initial Салат с фасолью и кукурузой highlights what was made.

Yes, absolutely.

• Мы сделали салат... = We made a salad...
• Мы приготовили салат... = We prepared a salad...

Both are natural.
Приготовили can sound a bit more specifically culinary, while сделали is very common in everyday speech.

So the original sentence is perfectly normal, but приготовили would also work well.

Because Russian has no articles.

So салат can mean:

• a salad
• the salad

The exact meaning depends on context.

In this sentence, English would normally say a salad, but Russian simply says салат.

Not exactly.

• на обед = for lunch
• в обед = at lunchtime / around lunch time

Compare:

• На обед мы сделали салат.
  = For lunch, we made a salad.
• В обед мы сделали салат.
  = At lunchtime, we made a salad.

So на обед focuses on the meal itself, while в обед focuses more on the time.

Yes, that is the most natural interpretation.

Because of сделали (perfective past plural), the sentence usually means:

• one completed action,
• done by we,
• at some specific occasion.

So the idea is: We made a salad with beans and corn for lunch
as a finished event.

If you wanted to talk about a habitual action, Russian would more likely use the imperfective:

• На обед мы делали салат с фасолью и кукурузой.

But even that would usually need more context to sound natural as a habitual statement.