Boil the pork belly. In a pot, combine pork belly, salt, peppercorns, garlic, and bay leaves. Add enough water to cover. Boil, then simmer for 45 mins to 1 hour until tender. Skim off fat scum as it cooks.
Score the pork. Let pork cool. Lightly slice the skin diagonally (just the surface), and slice the meat side across. This helps later when cutting into bite-sized pieces.
Dry the pork. Place on a rack or paper towels. Optional: poke tiny holes in the skin with a fork or toothpicks. Chill uncovered in fridge overnight to dry the skin.
Season and prep. Bring pork to room temp. Lightly season meat side with salt (and garlic powder or patis if you like). Wipe the skin with white vinegar using paper towel.
Cook until crispy. Air fryer: 200°C (400°F) for 35–45 mins, skin side up. Oven: 220°C (430°F) for 40–50 mins on a rack over a tray.
Slice and serve. Let it rest, then slice into pieces following your cuts. Serve with dipping sauce and rice!