The paper napkins you will encounter in Sicily, Italy are unlike those you may have encountered elsewhere. You will find them where paper napkins are usually found elsewhere, eg cafés, bars, cheap eateries, delis, and unassuming restaurants. Mid-to-high level (also mid-to-high priced) restaurants will usually provide cloth napkins, but you would be better advised to buy and bring your own with money you can save by going to a cheaper restaurant where the food is every bit as good.
Sicilian paper napkins amount to little more than squares of thin tissue paper, 15-20cm a side, and lack the thick, absorbent cellulose structure of normal paper napkins. Their wiping capacity is therefore slightly compromised. Don't panic. You have merely to spend an extra few seconds (and napkins) wiping your hands, face, proboscis1, whatever, before continuing on your travels. The extra time invested in cleanliness will be worth your while and much appreciated by any others you may encounter during your stay in Sicily.