Prepare the sauce: In a small bowl, whisk together the hoisin sauce, soy sauce, rice vinegar and sesame oil.
In a large skillet over medium-high heat, heat one tablespoon of oil. Add the onions and cook until softened (about 5 minutes), then stir in the garlic and ginger and cook until fragrant (1 minute more). Add the chicken and cook until it is no longer pink. If using ground chicken, break up the meat with a wooden spoon.
Pour in the sauce and cook until it has reduced significantly and the chicken is fully cooked. Turn off the heat and fold in the green onions. Season with salt and pepper.
Spoon rice, if using, and a generous scoop of the chicken mixture into the center of each lettuce leaf.
Notes
Serving this in large lettuce leaves looks really cool. Especially if you’re offering it as an appetizer, I highly recommend this presentation.Don’t hesitate to be patient and let the sauce reduce a lot; the final taste depends greatly on this.