HEAT greased grill to medium heat.
MIX turkey, egg white and 1/4 cup each cheese and salsa; shape into 4 (1/2-inch-thick) patties.
GRILL patties and vegetables 5 to 6 min. on each side or until burgers are done (165ºF) and vegetables are crisp-tender.
COMBINE remaining cheese and salsa. Serve burgers in buns topped with vegetables and cheese mixture.