Boil the tomatoes, onions, and two garlic cloves for 15 minutes. Remove from pot and blend. Set the mixture aside.
In a deep pot, place the pork, and add the blended mixture along with the meat seasoning, 2 chopped garlic cloves, chopped onion, chipotle, vinegar, oregano, cloves, bay leaves, salt, pepper, sugar, and enough water to submerge the pork.
Bring to a simmer and cover for 3 to 4 hours, stirring often to prevent sticking. Add salt and pepper to taste as it cooks.
Spoon the meat onto warm tortillas and top with your favorite salsa, cilantro, and chopped onions.