Trim any meat that is not covered by skin.
Puncture the skin of the pork belly many times with something sharp like a sharp skewer.
Blanch the pork belly in boiling water for 10 minutes, then refresh in cold water for another 10 minutes.
Once cool, dry with paper towels.
For a second time, puncture the skin of the pork belly many times.
Cut a crosshatch pattern on the lean side of the pork belly (not the skin side) about 5 mm deep.
Combine the Tbsp salt, 2 tsp sugar, 1 tsp ground ginger, 1 tsp five spice, 1 tsp tahini, 1 tsp sesame oil, and 1 Tbsp wine.
Lay the pork belly skin side down in a tray filled with the cup of rice vinegar.
Rub the marinade into the lean side of the pork belly.
Cover with plastic wrap and refrigerate overnight (at least 8 hours).
Take the pork belly out of the vinegar and wipe the vinegar off of the pork belly skin with paper towels.
Put back in the refrigerator, uncovered, for another 2 hours to dry completely.
Preheat the oven to 225 degC.
Wrap the pork belly tightly in a double layer of foil with just the skin exposed.
Mix the egg white into the cup of salt then spread it out evenly over the pork skin, being careful none goes down the sides between the pork and foil. Ensure all the skin is covered. If 1 egg white is not enough to make a paste with the salt, add a little more water.
Roast in the oven for 1 hour at 225 degC.
Remove from the oven, remove the salt, and puncture more holes in the skin.
Broil for 30 minutes or until the pork skin is golden and crispy.
Remove from the oven, remove the foil, and let sit on a rack over a tray for an hour.
Skin side down, cut the pork belly into appropriate sized pieces, about 15mm thick.