Boil tomatoes, onion, and two garlic cloves for 15 minutes. Remove from the pot and blend the mixture, then set it aside.
In a deep pot, place the pork and add the blended mixture along with the meat seasoning, the remaining two chopped garlic cloves, chopped onion, chipotle, vinegar, oregano, ground 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. Adjust salt and pepper to taste as it cooks.
Spoon the meat onto warm tortillas and top with your favorite salsa, cilantro, and chopped onions.