PREHEAT grill to medium-high heat. Toss vegetables and tomatoes with dressing. Place in center of 18-inch-long piece of heavy-duty foil. (Or, use double layer of regular foil.) Bring up foil sides. Double fold top and ends to seal packet, leaving room for heat circulation inside.
GRILL 8 to 10 min. or until vegetables are crisp-tender, turning after 4 min.
CUT slits in foil to release steam. Open packet. Sprinkle vegetable mixture with cheese.