Coarsely chop stir-fry vegetables; add to the pan. Stir in the teriyaki sauce, hoisin sauce, peanut butter, ginger, vinegar and oil. Stir-fry over medium-high heat for 5 minutes. Add garlic; cook 1 minute longer.
Remove from the heat; stir in onions. Place a scant 1/2 cup turkey mixture on each lettuce leaf; fold lettuce over filling. Serve with additional hoisin sauce if desired.