Wipe clean the dried chilies and remove the stems, seed and veins. Toast the chilies in a medium hot oven for a minute or two until they just start to change color, remove stems and seeds. Soak the toasted chilies in water for at least 30 minutes, drain and reserve the soaking water.
In a spice grinder, add the toasted cumin and coriander seeds. Grind into a fine powder.
In a blender, add the soaked chilies, tomatoes, onion, garlic, oregano, cumin, coriander, cinnamon and cilantro stems. Add about 1 cup of the reserved soaking liquid and blend, add more liquid if necessary to obtain a very smooth & thick consistency. Adjust the seasoning with salt and pepper.
Blot the short ribs dry with a paper towel and season well with salt. Heat the dutch oven over medium high heat, add the oil and wait until it shimmers. Add the short ribs and brown on all sides, be patient, this will take a few minutes per side. Once the beef is browned, remove and set aside.
Remove all but 4T. of oil from the pot and return to medium heat, add the reserved tomato-chili sauce, bring to a simmer and stir frequently, about 3–4 minutes. Stir in the tequila, and then return short ribs to pot.
Cover and place in 325°F oven. Cook for 2 hours, turning the short ribs over every once in a while. At 2 hours remove the lid, return to the oven to cook for 1/2 hour. This will reduce the sauce and deepen the color. Check for doneness by piercing the roast with a thin knife or fork. Once there is no resistance in the center, remove from the oven. Let cool in sauce. Degrease the sauce by ladling off any excess oil at the top. Adjust seasoning.
To server remove the beef from the sauce, gently pull the warm beef apart with two forks, pour the warm tomato-chili sauce over the pulled beef.
Toss everything together and serve immediately or drain before serving if made ahead. Adjust seasoning.
Queso Fresco: Corn tortillas, diced avocado seasoned with lime and salt
Serve to friends with more tequilla.