When ready to cook steak, heat gas or charcoal grill. When grill is heated, remove steak from marinade; pour marinade into measuring cup. Place steak on gas grill over medium heat or on charcoal grill over medium coals; cover grill. Cook 15 to 20 minutes, turning occasionally and brushing with marinade, until steak are desired doneness. Discard any remaining marinade. Let steak stand on platter 5 minutes; cut diagonally across grain into slices. If desired, garnish with cherry tomatoes and red onion slices.