Take the pork belly out of the fridge 15 minutes before grilling so it isn't ice-cold going onto the heat — cold meat seizes and cooks unevenly.
Mix the ssamjang: gochujang, doenjang, minced garlic, sesame oil, and sugar in a small bowl. Taste and adjust — it should be salty-sweet with a fermented kick, not just spicy.
Mix the dipping salt: sesame oil, flaky salt, and a few grinds of black pepper in a second small bowl.
Heat a heavy pan or tabletop grill over medium-high heat with no oil — the belly renders its own fat. Lay the pork slices in a single layer without crowding them.
Leave the meat alone for 2 to 3 minutes until the underside is deeply browned. Resist flipping early; a properly rendered crust releases from the pan on its own.
Flip once, then cook the second side another 2 minutes. Move the pieces to the cooler edge of the pan once cooked through, and use kitchen scissors to snip them into bite-sized pieces directly on the grill.
Push the rendered fat to one side and use it to sear the sliced garlic and the kimchi for 2 to 3 minutes each, until the garlic turns golden and the kimchi's edges char slightly.
Build each bite: a lettuce or perilla leaf in your palm, a small spoon of rice, a piece of pork, a dab of ssamjang or a dip in the sesame salt, a slice of grilled garlic. Fold and eat in one bite.