Place beef in a saucepan and add water to cover. Bring to a boil, reduce heat and simmer, covered, until the meat is very tender, about 1 hour; drain. When cool enough to handle, shred meat; set aside.
Combine beans, Red Chile Sauce, garlic and oregano in a food processor or blender; process until smooth. If mixture is too thick, add a little water or additional chile sauce.
Heat oil in a heavy skillet over high heat. Add reserved beef and cook, stirring, until well browned, about 3 minutes. Remove from heat and stir in black bean mixture. Season with salt and pepper.