HEAT greased barbecue to medium-high heat.
MIX turkey, 3 Tbsp. dressing and seasoning mix; shape into 12 thin patties. Combine cheese and 2 Tbsp. salsa; spoon onto centres of 6 patties. Cover each with second patty; pinch edges together to seal.
GRILL 7 min. on each side or until done (175ºF). Meanwhile, combine remaining dressing and salsa.
PLACE lettuce, tomatoes and burgers on bottom halves of buns; cover with salsa mixture and tops of buns.