Pre-heat oven to 500 degrees. In a small bowl mix the salt, chili powder, oregano, granulated garlic, and cumin. Coat the pork on all sides with the rub, massaging the spices into the meat. Let the pork sit at room temperature for 20 to 30 before browning.
In a food processor or blender, purée the tomatillos, canned chiles, garlic, onion, oregano, and beer.
Brown the roast on a roasting pan for 30 minutes in the oven.
Remove the pork from the oven and reduce temperature to 250 degrees. Place the pork in a 13x9-inch heavy-duty disposable drip pan. Pour the tomatillo mixture around the pork so it comes up the sides of the pork by 1 inch or so. Seal the pan tightly with foil, and place the pan in the center of the oven. Cook the pork until the internal temperature of the meat reaches 190°F and the meat is so tender that it tears easily with a fork, 2 1/2 to 3 1/2 hours.
When the pork is fully cooked, carefully remove the pan from the oven. Unwrap the pork (be careful of the steam) and transfer it to a cutting board. Chop the pork into 1/2-inch chunks and shreds, discarding any large pieces of fat or tough pieces of meat. Pour the pan liquid into a large saucepan and spoon off most of the surface fat. Add the shredded meat and simmer the mixture uncovered for a few minutes to blend the flavors. Season with the cilantro, Tabasco, as well as salt and pepper to taste. The chile verde may be made up to this point 1 day ahead of serving and refrigerated overnight. Warm the chile verde over a slow simmer before serving.
Serve the chile verde warm in bowls with steamed rice. Pass the sour cream, limes wedges, and a bottle of Tabasco.