In ca small bowl combine soy bean paste, honey , garlic powder, ginger powder, and 1 teaspoon of oil. Mix well. Spread the paste mixture to pork belly and rub all around. Let it sit for 15 minutes on the counter.
Preheat oven to 425ºF. Spray a rack with oil and place over baking pan (line the pan with foil for easy clean up).
Put the pork belly on the rack and drizzle a little more oil on top. Bake in the hot oven for 15 minutes. Reduce the heat to 350ºF and continue to bake for 20-30 minutes depends on the thickness of the meat. I used the very slim cut of pork belly which took very short time, about 30 minutes total. If using a slab of pork belly, it should take far longer. When inserted with a meat temperature, it should be around 165ºF.
Let the pork rest for a few minutes, then slice into desired size. Serve with onion salad over lettuce.
To make onion salad, soak the onion slices in cold water for 10 minutes. Drain well. Combine chili flakes, sugar, soy sauce, cinder vinegar, sesame oil, and sesame seeds in a bowl. Toss the onions with the dressing.