Лисички обычно солят.

Here it is the direct object, not the subject.

Russian often uses a verb in 3rd person plural with no expressed subject to mean people / they in general. So:

• солят = they salt
• Лисички обычно солят = People usually salt chanterelles
  or more naturally in English, Chanterelles are usually salted

A tricky point is that лисички looks like a nominative plural form, but for inanimate nouns the accusative plural is often identical to the nominative plural. So the form itself does not show the difference here.

Because Russian often leaves it out in this kind of sentence.

The verb солят already tells you it is 3rd person plural, and in Russian that can be used impersonally to mean:

• people
• they
• someone
• one (in a general sense)

So this is a very natural Russian way to express what people generally do, especially in recipes, customs, or general statements.

Because Russian uses the present tense for habitual or general actions.

So this sentence does not mean that the salting is happening right now. It means this is the usual practice.

Compare the idea in English:

• People usually salt chanterelles
• Chanterelles are usually salted

Both express a general habit, and Russian uses the present tense for that.

Because the sentence describes a usual, repeated, general action, and that calls for the imperfective aspect.

The verb here is from солить = to salt / to preserve by salting.

Imperfective is used for:

• repeated actions
• habitual actions
• general facts
• processes

Since обычно means usually, the imperfective is the natural choice.

A perfective verb would suggest a single completed event, which is not the point here.

Because Russian often prefers this active 3rd person plural construction where English would use the passive.

English naturally says:

• Chanterelles are usually salted

But Russian very naturally says:

• Лисички обычно солят
• literally: People usually salt chanterelles

This is often more idiomatic in Russian than forcing a passive structure.

It modifies the action солят.

So the meaning is:

• they usually salt
• not they salt in a usual way

It tells you that salting is the normal or typical thing people do with chanterelles.

Yes. Russian word order is flexible.

These are all possible:

• Лисички обычно солят
• Обычно лисички солят
• Лисички солят обычно

The basic meaning stays similar, but the emphasis changes a bit.

• Лисички обычно солят puts chanterelles first as the topic
• Обычно лисички солят emphasizes usually
• Лисички солят обычно can sound more contrastive or marked

The version you were given is very natural.

No. Лисичка can mean either:

• little fox
• chanterelle mushroom

So лисички can mean:

• little foxes
• chanterelles

Context decides which meaning is intended. In a food or cooking context, it means chanterelles.

It is accusative plural.

Why does it look like nominative plural? Because лисички is an inanimate noun here, and in Russian the accusative plural of inanimate nouns is usually the same as the nominative plural.

So:

• nominative plural: лисички
• accusative plural: лисички

That is why the form looks ambiguous at first.

Because Russian has no articles.

Russian does not have direct equivalents of a, an, or the. Whether the meaning is general, definite, or indefinite is understood from context.

Here the sentence is making a general statement about chanterelles as a type of mushroom.