1. Preheat the oven to 450 degrees . In a medium bowl, combine chickpea flour, water, salt and 1 tablespoon oil. Whisk with a fork until most lumps are dissolved; let sit 15 minutes.
2. Meanwhile, heat 1/2 tablespoon oil in a skillet over medium-high heat. Add sausage, bell pepper and onion and saute, stirring occasionally, until vegetables soften and links brown, about 10 minutes. Remove from heat.
3. Swirl remaining oil in an ovenproof skillet. Heat in oven 5 minutes; carefully remove. Rewhisk chickpea flour mixture, pour into skillet and bake 8 to 9 minutes, or until edges pull away and top looks firm.
4. Remove crust from oven; raise oven temperature to broil. Top crust with mozzarella and sausage-and-pepper mixture and return to oven for 3 minutes, or until cheese melts and edges are just beginning to brown.