Prep the lettuce. Separate lettuce leaves, rinse, and pat dry. Keep chilled so they stay crisp.
Make the sauce. In a small bowl, whisk 3 tablespoons soy or tamari, 2 tablespoons hoisin, 1 tablespoon rice vinegar, 1–2 teaspoons honey, 1 teaspoon cornstarch, 1 teaspoon toasted sesame oil, and 1–2 teaspoons sriracha. Adjust sweetness and heat to taste.
Heat the pan. In a large skillet over medium-high heat, add 1 tablespoon neutral oil.
When shimmering, add the white parts of the green onions, garlic, and ginger. Cook 30–60 seconds until fragrant.
Brown the turkey. Add ground turkey, breaking it up with a spatula. Season with a pinch of salt.
Cook 5–7 minutes until no longer pink and lightly browned.
Add the veggies. Stir in bell pepper, water chestnuts, and carrot. Cook 2–3 minutes until slightly tender but still crisp.
Pour in the sauce. Give the sauce a quick stir and add to the pan. Toss to coat and cook 1–2 minutes until glossy and slightly thickened.
Squeeze in half a lime. Taste and adjust seasoning.
Assemble. Fill lettuce cups with the turkey mixture. Top with green onion tops, sesame seeds, extra sriracha, and cilantro if using.
Serve with lime wedges.
Optional sides. Offer steamed rice, cauliflower rice, or rice noodles on the side for a heartier meal.