HEAT grill to medium heat.
MIX meat and pickles. Shape into 4 (1/2-inch thick) patties.
GRILL 6 to 7 min. on each side or until done (160°F), brushing occasionally with marinade. Top with Singles; cook 1 min. or until Singles are melted.
FILL buns with patties, lettuce, onion and tomato.