In a heavy pot, place the pork belly in and all of the ingredients for the cooking liquid and add water to cover. Bring to a boil over high heat. Reduce heat and simmer until pork is fully cooked through, and very soft, for 2 hours.
Remove the pork belly and place on a baking tray lined with foil to let cool. Discard the poaching liquid. Once cooled enough to handle, carefully cut off the skin of the pork and discard.
Preheat oven to 180°C.
Mix all of the rub ingredients together into a smooth paste and smear generously all over the top of the skin-side of belly. Place the pork in the oven, rub side up, and roast the pork until the top is nicely caramelized, about 30 minutes. Additionally you can place the pork under the grill briefly for a little more char.
Meanwhile, make the bossam sauce by mixing all of the ingredients together well in a small bowl. Set aside. Once the pork belly is nicely caramelized on top, let rest for 15 minutes in a warm place. Then transfer the pork to a cutting board and thinly slice into two-bite pieces. Serve the pork with the rice, lettuce leaves, bossam sauce, and pickled radish.
Try eating the pork in this way: Place a lettuce leaf in your hand. Scoop in a spoonful of rice, top with smear of sauce, piece of pork, and finish with some pickled radish. Wrap it all up together and take a bite. You’ll love it.