In a pan on medium heat, add enough vegetable oil to fry corn tortilla, once heated, fry tortilla until golden brown and crispy.
Once fried sprinkle tortilla with some taco seasoning (or salt & pepper if you have no taco seasoning).
Butter the outside of each slice of bread.
On the bottom slice, spread re-fried beans.
Cut fried tortilla in half, place one half on top of re-fried beans.
Sprinkle some of your Mexicana mix cheese on the tortilla, place your slices of avocado.
If making fresh salsa, combine all of the salsa ingredients in a bowl, then place on top of avocado. If using canned salsa, place 1-2 tablespoons on avocado.
Sprinkle queso fresco, chili powder and the rest of your Mexicana cheese mix on top of the salsa.
Spread one tablespoon of sour cream and one tablespoon of Mexican green sauce on the inside of your top slice of bread, and place on sandwich.
Place sandwich in pan, turn to medium heat, and cover pan. Cook until golden brown on each side.
Serve with sour cream or salsa if desired.