Preparation:

Cut the pork belly into small, uniform pieces.
Season the pieces with salt and black pepper to taste. If desired, add a tablespoon of vinegar to help crisp the skin.
Let it sit for at least 30 minutes to allow the seasoning to set.
Frying:
Heat a large skillet with enough oil to cover the chicharrones.
Place the chicharrones pieces in the skillet while the oil is still cold. This helps the fat gradually melt and makes the chicharrones crispier.
Cook over medium heat until it begins to boil. Then, increase the heat to high until the pieces are golden brown and crispy, stirring occasionally to ensure they fry evenly.
Remove the chicharrones with a slotted spoon and place them on a paper towel to absorb excess oil.