Preheat grill. Heat oil in large skillet and cook peppers and onion, stirring, 5 minutes or until tender. Remove and set aside.
Flatten each ball of dough on floured board into 6- to 7-inch circles. Lightly brush dough with a little oil.
Place dough, oiled side down on grill, lightly brush tops with oil. Grill 1 minute or until cooked on bottoms. Remove from grill, place on work surface grilled side up.
Spread 3 tablespoons sauce on each crust. Top with cooked onions, peppers, tomato and cheese.
Place pizzas on grill; cover and grill 2 minutes or until cheese is just melted. (If pizza bottoms begin to char move them to a cooler place on the grill.)