You can use fava beans or dried chickpeas (garbanzo beans) for falafel. The key is to use beans that are dried and not precooked. Canned beans do not work well for falafel.  Do not boil your beans before adding them to your mixture. This adds too much moisture to the mix. You want your beans just soft enough to break apart in the food processor–not in your hands. Your ground chickpeas will cook as they fry.