Devein the chiles and soak in hot water for 30 minutes.
Drain the chiles, combine all of the sauce ingredients in a saucepan, and simmer for 15 to 20 minutes. Add all ingredients into a blender and puree until smooth. Strain the sauce to remove any large particles. Season the sauce with the salt, to finish.
On a hot griddle, with the olive oil, saute the pork until fully cooked. Spread the refried beans on one side of the sub roll. Lay the pork on top of the refried beans, and top with the tomatoes, avocados, and onion. Sprinkle the sandwich with oregano and finish with a portion of the sauce.