Heat grill. In small bowl, combine all sauce ingredients; mix well. Set aside. Brush turkey patties on both sides with salad dressing. Cut off 1 inch from top of each pita bread. Wrap pita breads in foil using double-fold seals.
When ready to grill, place patties on gas grill over medium heat or on charcoal grill 4 to 6 inches from medium coals. Cook 8 to 10 minutes or until no longer pink in center, turning once. Heat foil-wrapped pita breads on grill as turkey cooks.
Fill pita breads with cooked turkey, tomato and lettuce. Spoon sauce into sandwiches.