While it simmers, put your oil in a large skillet. Should be about 1/2″ deep. Begin heating it to 300ºF.
Stack the tortillas on a cutting board and use the tip of a knife to make 8-10 small (1/4″) slits in the tortillas. Stab them gently all over. This helps prevent tortilla balloons and they stay flatter and more stackable.
When oil if hot, fry tortillas one at a time for just about 30 seconds on each side until golden. Drain on paper.
Once all are fried, lay 4 out on a baking sheet. Spread each with a couple tablespoons of refried beans, 1/4 cup taco meat, a tablespoon or two of sauce, a tablespoon of cheese. Top with another shell. Spoon 2-3 more tablespoons of sauce and cheese on top.
Broil on low heat for just a few seconds until the cheese is melted.
Sprinkle with tomatoes, green onion, and a top with sour cream.