Pat the pork skin dry then scrape it thoroughly with a knife to remove any debris. Poke holes into the skin with the tip of your knife all throughout the surface. Score the skin in ½ inch strips.
Rub salt to cover the skin.
Take a rolled-up kitchen towel and place it under the board to create a slope. Brush a thin layer of vinegar over the top of the skin and let it air dry. Brush a second thin layer of vinegar over the top and let it air dry.
Set uncovered in your fridge overnight.
Preheat your oven to 450 degrees Fahrenheit.
Set up a sheet pan with a rack in it.
Place the skin on the rack fat down. Dry the skin with a paper towel. Rub it down with oil. Sprinkle some more salt on it.
Put a second sheet pan on top of the skin and a dutch oven on top of that sheet pan.
After 45 minutes, remove the top sheet pan and let the skin cook until it is golden brown, and has bubbled all over.