Preheat your oven to 325°F. Use a sharp knife to score the pork belly skin in a 1-inch crosshatch pattern, being careful to cut through the skin and fat but not deep into the meat.
Pat the pork belly completely dry with paper towels, then rub the salt and black pepper evenly over all sides of the meat.
Place the pork belly on a wire rack set inside a baking sheet, skin-side up. Roast for 1 hour and 30 minutes, until the fat has rendered and the meat is tender.
While the pork roasts, make the glaze by whisking together the honey, soy sauce, rice vinegar, minced garlic, grated ginger, and water in a small saucepan. Simmer over medium-low heat for 5 minutes until slightly thickened, then remove from heat.
Remove the pork belly from the oven and increase the oven temperature to 425°F. Brush half of the honey glaze evenly over the top and sides of the pork belly.
Return the glazed pork belly to the hot oven and roast for 15-20 more minutes, until the glaze is bubbly and caramelized and the skin is crispy. Let rest for 10 minutes before slicing and serving with the remaining glaze.