Put Carrot (1 cup), Daikon (1 cup), Distilled White Vinegar (1 cup), Water (3/4 cup), Granulated Sugar (1/4 cup) into a jar, put the lid on tightly, then shake the jar gently to combine the ingredients. Allow to brine in the fridge for at least an hour, or up to 1 month.
Prepare the sauce for the pork filling by combining the Soy Sauce (3 tablespoon), Fish Sauce (1 teaspoon), Brown Sugar (1 1/2 tablespoon), and Dark Soy Sauce (1/2 teaspoon).
Heat the Peanut Oil (2 tablespoon) in a wok over medium high heat.
Saute the Onion (1) until it turns a little translucent. Add the Garlic (2 clove) and Lemongrass (3 stalk). When the garlic starts to turn brown, remove this mixture from the wok and set aside.
Add the Ground Pork (1 pound) to the wok and stir-fry until no longer pink. Return the onion and garlic mixture to the wok. When ground pork has cooked all the way through, stir in the sauce and mix well until the ground pork is thoroughly coated in the sauce.
Transfer to a serving dish.
To assemble the lettuce wraps, place some of the ground pork filling on to a Butter Lettuce (1 head) leaf. Squeeze a light layer of Japanese Kewpie Mayonnaise (to taste) over the ground pork.
Top with pickled carrot and daikon, Fresh Cilantro (to taste), and a Red Chili Pepper (1).