If there is any hair on the pork skin, scrape it off with a knife. Then wash the pork belly under a tap.
In a fry pan on medium high, add the water, salt and sugar.
Once boiling add the pork belly skin side down and cook for 8 minutes on each side.
Once done, remove the pork belly and let it cool on a rack. Pat dry with some paper towel when it is cool enough to do so.
Get a meat skewer or a metal fork and punch lots of holes into the skin of the pork belly - this usually takes me about 5 - 10 minutes. Do not punch holes so deep that it reaches the meat.
Brush the pork skin with vinegar and then sprinkle half the salt. Let it rest for 10 minutes and repeat the process.
Put the pork belly into the fridge uncovered and allow the skin to dry for a minimum of 12 to 48 hours. If you can, check on it every now and then to wipe off any moisture that comes to the surface.
Take your pork belly out of the fridge and apply the meat rub on the sides and the bottom of the pork belly.
Preheat your air fryer for 5 minutes then cook the pork belly for 40 minutes at 200 C (392 F).
Once done, let it rest for 15 minutes before cutting.