Eating in a restaurant gives you a lot more flexibility. There are 4 courses, antipasti, primi, secondi and postre. You can order from any and more importantly you don't have to order from all of them. The primi is going to be the one with pasta so if this is a problem you can opt for something else or just order the antipasto to have with bread. Similarly the secondi is meat or fish and you choose the vegetables with potatoes as an option. Some dishes come with a few potatoes but you can check. The postre is where you find the cakes, fruit and gelati.
A great Sicilian speciality is caponata which is aubergine, peppers, celery, tomatoes, olives and capers and quite delicious. I would avoid the cannoli.
Italian restaurants are on the whole very flexible, more touristy ones maybe not so much, on one occasion my wife and I just two two antipasti and that was no problem. Our moment of revelation was in a restaurant in Rome where a man came in and ordered what he wanted rather than what was on the menu. At lunch time you will also find a menu del giorno in most with a list of what's on offer with two or three courses at a fixed price and you can look at what others are eating before you choose.