Preheat the oven to 300˚F.
Place the ribs on a foil-lined rimmed baking sheet, sprinkle with salt, cover with another piece of foil, pressing down around them to tightly cover the ribs, and bake for about 3 hours, until the ribs are very tender. If you like, pre-cook the ribs up to this point, cool and refrigerate for up to 3 days; finish in the oven or on the barbecue.
Meanwhile, in a medium bowl, stir together the brown sugar, gochujang, vinegar, soy sauce, garlic and ginger.
Uncover the ribs, turn the heat up to 450˚F (or preheat the barbecue to medium-high), brush the ribs with sauce and bake or grill for 10-20 minutes, until the sauce has darkened and caramelized.