Make the sauce: in a small bowl combine the hoisin sauce, soy sauce, rice wine vinegar, sriracha, and sesame seed oil.
In a large skillet, heat the olive oil over medium-high heat and saute the onions, garlic, and freshly grated ginger until fragrant, about 1 minute.
Mix in the ground chicken and cook until no pink is left.
Finally, pour in the sauce and simmer for 1-2 minutes.
Turn off the heat and stir in the water chestnuts and green onions. Season with salt and pepper. Serve over lettuce leaves.