In a skillet over medium heat, add chiles and roast, stirring regularly, for about 20 to 30 seconds or until lightly browned. Remove from pan and place in a bowl with enough hot water to cover. Soak for about 15 to 20 minute or until softened. Remove and discard stems.
In a blender, combine stemmed chiles, tomato, onion, garlic, vinegar, oregano, cinnamon, cloves, and salt and pepper to taste. Process until smooth and the consistency of a thick paste. Set aside.
In a thick-bottomed pot over medium heat, heat oil. Add pork and cook, turning as needed, until lightly browned. Remove and discard any excess oil from pan.
Add chili paste and stir together to fully coat meat. Add water and bring to a boil, skimming any scum that may float on top. Lower heat, cover and cook for about 1 1/2 to 2 hours or until meat is fork tender and sauce is reduced. Season with salt to taste. Serve hot.