Heat the olive oil in a small frying pan over low heat. Add the kaffir lime leaves and lemon grass and sauté for 15 minutes. Turn off heat and allow to sit another 15 minutes before straining lemongrass and kaffir lime leaves out of oil. Keep the oil, discard the leaves and lemongrass.

In a large bowl, mix together all of the remaining ingredients except the kaiser rolls. Once combined, cover the bowl with plastic wrap and refrigerate for 1 hour. While it is marinating, you can prepare the boy choy and pork belly.

For the bok choy, heat the sesame oil, soy sauce, brown sugar, and fish sauce in a large frying pan over medium heat. Add the baby bok choy and cook until the greens are wilted and the large stems are lightly golden on the places where they're touching the pan, about 25 minutes, stirring every 5 minutes. Remove and cool the boy choy in a strainer.

For the pork belly, heat the olive oil in a medium-sized frying pan and add the pork belly slices. Fry until lightly browned and crispy on both sides, about 10-15 minutes total.

When the burgers are done marinating, form them into 5 large patties. Heat the grill to medium-high and cook the burgers until the internal temperature reaches at least 145 degrees Fahrenheit.

To assemble the burgers, spread 1 tablespoon of mayonnaise on each of the bottom kaiser buns. Place a few leaves of the bok choy on the bottom kaiser bun, place the pork burger on top, then the pork belly on top of the burger, and crown with the top of the kaiser roll. Serve immediately.