Heat the oil in a wok or very large skillet set over medium-high. Add next 6 ingredients and stir-fry 3 minutes. Add the teriyaki sauce mixture and water and bring to a simmer. Mix in the tofu and green onions and cook 1 to 2 minutes, or until heated through. Spoon the stir-fry into a serving dish and set on the table. Let guests fill the lettuce leaves, as desired, with the stir-fry.