In a bowl, combine pork, onions, garlic, bay leaves, salt, and pepper. Place in the refrigerator and marinate for about 30 minutes.
In a wide, heavy-bottomed skillet over medium heat, heat oil. Add meat mixture and cook, turning occasionally, until pork is lightly browned.
Add vinegar and allow to boil, uncovered and without stirring, for about 3 to 5 minutes.
Add soy sauce and water and stir to combine. Allow to a boil for another 3 to 5 minutes.
Lower heat, cover, and simmer for about 40 to 50 minutes or until meat is fork-tender and sauce is reduced.
Season with salt and pepper to taste. Serve hot.
