Combine ingredients for meat in a heavy saucepan; simmer covered until tender. Cool and shred to desired consistency, leaving in pan. Cover. Set aside.
While meat is cooking, mash garlic cloves with cumin and salt to form a paste. Mix in the oregano. Remove stems from dried anchos. Simmer the ancho chiles in the water in a saucepan for about 15 minutes, until soft. Saving the water, place the chiles into a blender and liquefy with some of the water. Add the garlic mixture and enough of the remaining water to form a fairly thin sauce. You can strain this to remove any seeds if you like.
To finish off the dish: Uncover the pork. Return to heat and cook away the remaining water. Sprinkle meat with flour or cornmeal. Saute until starting to brown. Add the sauce and any remaining chile cooking water if you like it really juicy. Simmer for 15 minutes, adjusting the consistency if necessary as the sauce thickens. Add more flour or cornmeal if it is too thin.
Serve with warmed flour tortillas, rice and refried beans with desired garnishes. The restaurant served it with refried beans and cubed potatoes, soft fried with bell peppers and onions. YUMMY!