Wash lettuce leaves and pat dry. Set aside.
In a large skillet, heat half of the oil over medium-high heat. Add the chicken, onion, and garlic, and cook for about 5 to 7 minutes, or until the meat is browned. Transfer the meat mixture to a colander.
In the same skillet, heat the remaining oil over medium heat. Add the rest of the ingredients to the pan, along with the chicken, and stir to combine. Cover and cook for 10 minutes, or until the zucchini is tender.
Spoon the chicken into the lettuce leaves. Garnish with fresh cilantro and chili flakes for extra flavor and visual appeal.
