In a large skillet, heat the sesame oil over medium heat. Add the minced garlic and grated ginger, sautéing for about 1 minute until fragrant.
Add the ground chicken or turkey to the skillet, breaking it apart with a spatula. Cook until the meat is browned and cooked through, approximately 5-7 minutes.
Stir in the chopped water chestnuts and green onions, cooking for an additional 2-3 minutes to combine the flavors.
Pour in the soy sauce, rice vinegar, and sriracha (if using). Mix well and let simmer for another 2 minutes to allow the sauce to thicken slightly.
Remove the skillet from heat and stir in the chopped cilantro.
To serve, spoon the filling into the lettuce leaves, garnishing with chopped peanuts or cashews if desired. Enjoy immediately for the best texture.