So today, in Stresa, let's look at the loos. Truth is, there are not many. These are the ones that I know of:

This one, marked WC, is located just on the eastern edge of the large parking lot in front of the Stresa imbarcadero.

Down at the other end of Stresa, at the cableway station at Carciano, there is one, locked at the time that I checked it. And there are restrooms at the train station as well.

That all being said, I will advise that it is also possible to find restrooms at most every bar and restaurant in Stresa. So, while walking, stop in for a quick cappuccino, or buy a bottled water, and feel free to use the facilities. Another option is to stop in to one of the large hotels along the lake and ask for the public restrooms.

And how to ask? The proper thing to ask for is il bagno, the bathroom. If you are asking in English ask to use the bagno. If you are asking in Italian, you should say, "Dove e' il bagno? (Where is the bathroom?)" or, "Sa dove c'e' un bagno? (Do you know where there is a bathroom?)"