Place the pork belly in a large pot.
Add the pounded garlic, bay leaves, whole peppercorns, and salt.
Pour in the water.
Bring to a boil, then reduce the heat and simmer for 1 to 1½ hours, or until the pork is fork tender.
Remove the pork from the cooking liquid and place the pieces on a cooling rack.
Allow the pork to dry for approximately 1 hour in front of an electric fan.
Pour the cooking oil into a deep, heavy pan suitable for frying.
Heat the oil until hot. Once hot, reduce the heat to low and allow the oil to settle before beginning the long first fry.
Carefully add the pork and fry over low heat for at least 1 hour. Immediately cover the pan for the first few minutes, as the oil may splatter when the pork is first added.
Remove the cover once the oil has settled down. Leaving the pan uncovered allows moisture to escape instead of being trapped inside the pan, helping the pork skin dry out gradually during the first fry.
After 1 hour, check the skin. If it is still soft, continue frying for another 15 minutes.
If the skin still hasn't started to blister, slightly increase the heat to medium and fry for about 3-5 minutes, or until you see small blisters forming.
Remove the pork from the oil and place it on a rack.
Let the pork rest for about 30 minutes in front of an electric fan.
For the second fry, increase the heat to high and allow the oil to become very hot.
Carefully return the pork to the hot oil and fry for approximately 1 minute, or until the skin becomes beautifully blistered and crispy.
Remove from the oil and drain.
Slice and serve with vinegar dip.