Sciacquando i piatti, penso alla passeggiata di domani.

Sciacquando means while rinsing or as I rinse.

It is the gerundio (gerund) of sciacquare = to rinse. In Italian, this form is often used to describe an action happening at the same time as the main action:

• Sciacquando i piatti, penso... = While rinsing the dishes, I think...

So the sentence has:

• a background/simultaneous action: sciacquando i piatti
• a main action: penso

Both are possible.

• Sciacquando i piatti, penso...
• Mentre sciacquo i piatti, penso...

They both mean roughly while I rinse the dishes, I think...

The difference is mainly stylistic:

• sciacquando is more compact and slightly more written or narrative in feel
• mentre sciacquo is often more explicit and straightforward for learners

One important grammar point: with the gerund (sciacquando), the subject is normally understood to be the same as the subject of the main verb. Here, the person rinsing is also the person thinking.

Because Italian usually drops subject pronouns when they are not needed.

The verb penso already tells you the subject is I:

• penso = I think

So:

• (Io) penso = I think

Italian only adds io for emphasis, contrast, or clarity:

• Io penso alla passeggiata, non lui. = I’m thinking about the walk, not him.

Italian often uses the definite article where English may not.

So:

• i piatti = the dishes

In a sentence like this, i piatti refers naturally to the dishes being washed/rinsed, so the article sounds normal and expected.

This is very common in Italian:

• Lavo i piatti = I wash the dishes
• Mi lavo le mani = I wash my hands

English often omits or changes articles in ways Italian does not.

They are related, but not identical.

• lavare i piatti = to wash the dishes
• sciacquare i piatti = to rinse the dishes

So sciacquare is more specific: it refers to the rinsing stage, usually after washing with soap.

That means this sentence is quite literal:

• Sciacquando i piatti... = While rinsing the dishes...

If you wanted the broader idea while doing the dishes, Italian would often use:

• Lavando i piatti...

Because the verb pensare in the sense of to think about takes the preposition a.

So:

• pensare a qualcosa = to think about something

Since passeggiata is feminine singular and uses la, the preposition and article combine:

• a + la = alla

So:

• penso alla passeggiata = I’m thinking about the walk

More examples:

• Penso al lavoro = I’m thinking about work
• Penso ai miei amici = I’m thinking about my friends

Italian commonly uses di + time expression to mean for/of tomorrow, tomorrow’s, and similar ideas.

So:

• la passeggiata di domani = tomorrow’s walk / the walk tomorrow

This is a very normal structure:

• la lezione di domani = tomorrow’s lesson
• la partita di stasera = tonight’s match/game
• il viaggio dell’anno prossimo = next year’s trip

Italian does not form possession the way English does with ’s, so di is often the natural equivalent.

It can correspond to either in English, depending on context.

Italian present tense often covers both:

• I think
• I’m thinking

Here, because of the situation, English would often prefer:

• While rinsing the dishes, I’m thinking about tomorrow’s walk

But grammatically, Italian simply uses the present:

• penso

This is very common in Italian.

Here it most naturally means while or as rinsing the dishes.

• Sciacquando i piatti, penso... = While rinsing the dishes, I think...

It describes a simultaneous action, not a method.

If it meant by rinsing the dishes, that would suggest rinsing is the means of thinking, which does not fit the sentence.

So the best interpretation is:

• during the action of rinsing the dishes

Yes. Italian word order is flexible.

You could also say:

• Penso alla passeggiata di domani sciacquando i piatti.

This means essentially the same thing:

• I think about tomorrow’s walk while rinsing the dishes.

However, putting sciacquando i piatti first makes the scene feel a bit more natural or literary, because it sets the background action first.

Yes, a couple of things may catch an English speaker’s eye.

• sci in Italian sounds like sh
  So the beginning of sciacquando sounds like sha...

• qu is pronounced like kw

A rough guide is:

• sciacquando ≈ shah-KWAN-do

Also, the scia part is not pronounced like English see-a. It is a single smooth sha sound.

Yes, it can.

The structure suggests an everyday action in the background (rinsing the dishes) while the mind is focused on something else (tomorrow’s walk). So it can sound reflective, casual, or slightly daydreamy.

That is one reason the gerund works well here: it creates a sense of an ongoing background activity while the speaker’s thoughts move elsewhere.