Preheat the oven at 375°F.
Prepare a high-sided aluminum or foil-lined tray and place it over a rack, which sits atop another tray filled with water. This setup ensures even cooking and moisture retention. Transfer the marinated pork belly onto the high-sided aluminum tray, skin side up.
Rub rice wine vinegar onto the skin of the pork belly. Rub the salt onto the skin.
Place the tray with the pork belly in the preheated oven on the middle rack. Roast the pork belly for 1 hour 30 mins until the skin is crispy and golden brown.
Remove the tray from the oven and with a spoon remove any excess salt from the skin, then return the pork belly to the oven and broil it on the lowest rack for 5 minutes, or until the skin is golden crispy and bubbly.
Allow the pork belly to rest for 15 minutes before slicing and serving.