Make the sauce. In a small bowl, whisk together soy sauce, rice vinegar, hoisin, chili-garlic sauce, sesame oil, cornstarch, and water. Taste and adjust heat and sweetness as you like.
Prep the lettuce and toppings. Separate lettuce leaves, rinse, and pat dry.
Slice green onions, chop cilantro, and set out any extras like cucumbers and lime wedges.
Sauté aromatics. Heat oil in a large skillet over medium-high heat. Add onion, garlic, and ginger. Cook 2–3 minutes until fragrant and softened.
Cook the turkey. Add ground turkey to the skillet, breaking it into small pieces.
Cook 5–7 minutes until no pink remains and any moisture cooks off. Season lightly with salt and pepper.
Add veggies. Stir in bell pepper, carrots, and water chestnuts. Cook 2–3 minutes so the veggies stay crisp-tender.
Sauce it up. Pour the sauce over the turkey mixture.
Stir and simmer 1–2 minutes until glossy and slightly thickened. If it gets too thick, add a splash of water.
Finish and taste. Remove from heat. Stir in half the green onions.
Taste and adjust salt, heat, or acidity with a squeeze of lime.
Assemble. Spoon the spicy turkey into lettuce leaves. Top with remaining green onions, cilantro, sesame seeds, and any extras you like. Serve immediately.