Place halved tomatoes (in batches), garlic, onion, half of the oregano, cloves, black pepper, chiles, and a bit of water in a blender. Blend until smooth and then run through a sieve.
Heat the oil in a large casserole (large enough to hold all the meatballs in one layer). Fry the tomato mixture in the oil until its color changes to a deeper red, about 10 min. Season the sauce with salt and pepper. Set aside ½ cup of the sauce. Reduce heat to low and simmer, stirring occasionally.
Cut the bread in chunks and place in a bowl with the water for about 8 min or until soft. Squeeze out the excess water. In a big bowl, mix together the meats, salt and pepper, the rest of the oregano, capers, moistened bread, egg, and enough of the reserved tomato and chipotle sauce to create a mixture that allows for making meatballs that are firm but not dry. Add more egg or bread if needed.
Start making your meatballs. They should be slightly larger than a golf ball, each weighing about 2 ounces. When all your meatballs are done, place them at once, without overlap, into the simmering tomato chipotle sauce. Bring the heat up to med-low and cook meatballs for 30 min, until meat is fully cooked and firm. If the sauce doesn’t fully cover the meatballs, cook for 15 min, flip them over, and cook the other side for the remaining time.
Serve with a chipotle on the side, Mexican white rice, whole or refried black beans, and a basket full of white corn tortillas.
Note: it is important to place all the meatballs at once in the tomato sauce, so they will cook at the same time.