In a large nonstick skillet coated with cooking spray, cook and stir the turkey over medium-high heat until no longer pink. Coarsely chop mixed vegetables; add to the pan. Stir in teriyaki sauce, hoisin sauce, peanut butter, ginger, garlic, vinegar and oil. Cook and stir over medium-high heat for 5 minutes or until heated through. Remove from heat. Stir in onions. Place a 1/2 cup turkey mixture on each lettuce leaf; fold lettuce over filling. Serve with additional hoisin sauce, if desired.