In a small bowl combine all the ingredients for the sauce and mix well. Set aside.
In a large saute pan combine the onion, ginger, garlic, and olive oil. Cook for 3 minutes.
Add in the chicken and cook for 3-4 minutes or until it is cooked through.
Add the sauce and cook for 3-5 minutes or until the chicken absorbs most of the sauce.
Sprinkle with sesame seeds and green onions.
Place several tablespoons of chicken mixture on each lettuce leaf and enjoy!