Combine orange juice and cornstarch in small bowl. Saute lamb in heavy large skillet over high heat until cooked through, breaking up with back of spoon, about 5 minutes. Pour lamb with its juices into colander; drain. Heat oil in same skillet over high heat. Add ginger, garlic and orange peel; stir-fry 30 seconds. Add green onions 30 seconds. Add hoisin sauce and lamb to skillet; stir until blended. Add orange juice mixture; stir until thickened, about 1 minute. Spoon into lettuce leaves.