Mix together the rice vinegar, soy sauce, oyster sauce, sugar, and sesame oil in a bowl and set aside.
Heat a flat bottom saute pan over medium-high heat and add vegetable oil. When oil is hot, add the garlic and cook for about a minute, taking care not to burn. Stir in greens and peppers and cook, stirring constantly for approximately two minutes (the oil will pop). Add the pre-made sauce into the lettuce and cook for one more minute.
Serve with sesame-crusted tuna on top. Garnish with black and white sesame seeds and pickled vegetables of your choice.