Add the pork belly and marinade to a chamber vacuum seal bag and use a chamber vacuum sealer to seal. Alternatively, add to a freezer-safe zipper top bag and use the "arm method" to remove the air.
Add the sealed bag to the preheated water bath and cook for 8-10 hours. Use sous vide magnets or a ceramic plate to make sure the bag doesn't float while cooking.
When the pork belly is done sous viding, finish for a crispy texture. To finish on the smoker, smoke at 200 degrees F for 2 hours. To finish in the oven, place a wire rack over a baking sheet and cook at 350 degrees for 20-30 minutes. To finish in the air fryer, cut the pork belly into 1 inch cubes and air fry at 380 degrees F for 12-15 minutes.
Serve with rice, kimchi, and sliced green onions or as desired.