Stir together milk, carrot, green onion, bread crumbs, Italian seasoning, garlic salt, and pepper in a medium mixing bowl. Add ground turkey; mix well. Shape the mixture into four 1/2-inch-thick patties. Lightly grease the grill rack.
For a charcoal grill, place patties on the rack of an uncovered grill directly over medium coals. Grill for about 12 minutes or until an instant-read thermometer inserted into the side of a patty registers 165 degrees F, turning once.
For a gas grill, preheat grill. Reduce heat to medium-hot. Place patties on grill rack; cover and grill patties as directed in step 2.
Meanwhile, stir together mustard and curry powder.
Serve patties topped with lettuce leaves, zucchini, sliced tomato, and curry mustard mixture.