HEAT greased grill to medium-low heat.
FILL bread slices with Singles, bacon, tomatoes and avocados to make 2 sandwiches. Spread outsides of sandwiches with margarine.
GRILL with lid closed 4 to 6 min. or until cheese is melted and bread is grill marked, turning once.
MEANWHILE, mix Miracle Whip and salsa. Serve as a dip for the sandwiches.