Heat gas or charcoal grill to medium heat. Cut 14 x14-inch piece of heavy duty foil; spray foil with cooking spray. Place dough on foil; starting at center, press dough to 12-inch round. Place dough on grill, foil side down. Cook, uncovered, 3 minutes or until bottom of crust is light golden brown. Remove from grill.
Using wide spatula, flip crust over on foil so uncooked side is down. Spread pizza sauce evenly over crust. Sprinkle with mozzarella cheese. Arrange bell peppers and onions over cheese; sprinkle evenly with Parmesan cheese.
Place pizza onto grill, foil side down. Cook, covered, an aditional 3 to 4 minutes or until crust is golden brown and cheese begins to melt.