1. Rinse the pork and pat dry with paper towels. In a bowl, mix together vinegar, soy sauce, tomato sauce, hot sauce, sugar, salt and pepper. Add water and mix again.
2. In a skillet, heat the olive oil over medium-high heat. the pork on all sides, about 3-5 minutes per side.
3. Place the onion slices to a medium pot, place the meat on top of the onions. Add garlic and pour the prepared sauce over the meat.
4. Cover and cook for 3-4 hours, until the meat is very tender and almost falling apart.
5. Let rest for 10 minutes, slice and serve (especially good over pasta).