Heat a large skillet over medium-high heat with 1 tablespoons oil. Add the ground turkey and cook, breaking it down with a wooden spoon, until browned and crispy. Stir in the red onion, garlic and half of the scallions. Toss and cook for about 3 minutes to soften.
Add the remaining veggies and cook for another 5 minutes until tender. Mix in the hoisin, soy sauce, sriracha, salt and pepper. Cook for 1 to 2 minutes to thicken the sauce. Serve in lettuce leaves with the remaining scallions as garnish.