Sauce: In a small bowl, combine garlic, ginger, cilantro, sesame seeds, tamari, lime juice, vinegar, fish sauce (if using), sesame oil and maple syrup (if using). Set aside.
Stir-fry: In a large skillet, heat olive oil over medium high heat and add chicken and cook until it's no longer pink. Add celery, carrot, red pepper, peas and onion. Stir fry for a few minutes. Stir in garlic, mushrooms and ginger. Add half the sauce to the pan. Cook for 1-2 more minutes then transfer to a large bowl and top with green onions.
Lettuce wraps: Fill lettuce leaves with stir fry and top with bean sprouts, cilantro and cashews. Drizzle remaining sauce over top as desired.
EnJOY!