Puncture & Prep: Pat the pork belly bone-dry with paper towels. Using a meat tenderizer or skewers, puncture thousands of tiny holes only into the skin. Do not hit the meat!
Score the Meat: Flip the pork over. Score the meat side in a 1-inch diamond pattern, about 1/2 inch deep.
Marinate: Rub the Five-Spice, Paprika, and fine salt thoroughly into the meat side and scored crevices.
The Salt Shield: Flip back and wipe the skin perfectly clean. Brush with vinegar, cover with a thick layer of coarse sea salt, and let sit for 30 minutes at room temperature.
The Cold Dry: Wipe the skin completely clean of salt and moisture. Place the slab on a plate, skin-side up, and leave it uncovered in the fridge for 24 hours.
The Foil Boat: Preheat your Air Fryer to 380°F. Build a snug aluminum foil "boat" around the sides of the pork, leaving only the skin exposed.
The First Roast: Place the boat into the Air Fryer basket. Roast for 30-40 minutes (depending on your air fryer) to render the fat and tenderize the meat.
The High Broil: Crank the Air Fryer to 390°F. Watch closely for 10-15 minutes as the skin blisters into a golden, bubbly honeycomb.
The Rest: Remove once the skin passes the "zipper" scrape test. Rest for 20 minutes before slicing with a heavy cleaver.
The Noodles: Prepare the dried Bánh Hỏi by blanching for exactly 1 minute and 15 seconds. Remove and roll into "cigars" immediately; the residual steam will finish the cooking.
Serve: Brush the noodles with Scallion Oil and arrange on banana leaves alongside the crispy pork slices, pickled carrots and daikon and fresh herbs. Serve with Nước Mắm Chấm.