The only way to grill pork belly is to render out some fat first. Otherwise, the fat drips into the grill and creates an inferno that incinerates the meat. A low, slow braise in the oven gets the job done. Then you can grill the belly and get a good, crisp exterior. At the very end of cooking, we like to glaze it with our version of ssam jang, a thick Korean spice paste. Wrap pieces of grilled belly in lettuce leaves with sticky rice, kimchi, and more spice paste and you have a knockout small plate or first course. You can buy ssam jang in Asian markets, but it’s easy enough to stir it up yourself.
Preheat the oven to 300°F (150°C). Rub the pork belly all over with the salt and set the pork, fat side up, in a baking dish just a little bigger than the pork itself. Add the unseasoned rice vinegar to the baking dish; it should come about halfway up the sides of the pork. Cover the baking dish tightly with aluminum foil and braise the pork in the oven for 3 hours.
Remove from the oven and let cool, still covered, to room temperature. When cooled, uncover the baking dish and then peel off and discard the skin and the top layer of fat that comes off with the skin. Cut the pork into bricks about 2 inches (5 cm) long and 1 inch (2.5 cm) wide.
Heat a grill for medium-high direct heat (400°–450°F/200°–230°C). Brush the grill grate and coat with oil. Place the belly bricks, meat side down, on the grate and sear on all sides, 2–3 minutes per side, including the ends. Grill the fatty side last. During the last few minutes, brush the bricks all over with the ssam jang. Transfer the pork to a plate.
Put the rice into a serving bowl, add the seasoned rice vinegar, and stir and toss to mix evenly. Invite your guests to wrap the pork belly in lettuce leaves with a little rice, more ssam jang, and some kimchi (if using).
In a small bowl, combine all of the ingredients and mix well. Use immediately, or store in an airtight container in the refrigerator for up to 1 week.