1Heat closed medium-size contact grill for 5 to 10 minutes. In small bowl, mix beef, 1 tablespoon marinade, the water chestnuts, pepper, onions and garlic. Shape mixture into 2 patties, each about 3/4 inch thick.
2Place patties on grill. Close grill. Grill 8 to 10 minutes, brushing with 1 tablespoon marinade, until meat thermometer inserted in center of patties reads 160°F.
3Serve burgers on bread; top with bell pepper rings.