1. Preheat oven to 400 degrees F. Stack the tortillas and cut them in sixths. Place on a baking sheet and bake until crisp (4-5 minutes). Remove from the oven and set aside.
2. Set the broiler to high and set the rack to the highest position. Line a baking sheet with aluminum foil. Place the tomatoes, onion, and jalapeños on the baking sheet and broil until the skins blacken (4-5 minutes). Turn the vegetables over and broil the other side until blackened (3-4 minutes). Transfer to a bowl, cover, and let cool until safe to handle (10-15 minutes).
3. Preheat oven to 350 degrees F.
4. Peel the tomatoes. Wearing gloves, peel and seed the jalapeños. Place the vegetables in a blender or food processor with cilantro and 1/2 teaspoon salt. Pulse to make a chunky sauce.
5. In a large frying pan, heat 2 1/2 tablespoons of the oil over medium-high heat. Add the garlic and saute until golden (1-2 minutes). Stir in the beans and remaining 1/2 teaspoon salt and cook until heated through (3-4 minutes). Remove from the heat.
6. Grease a large baking dish with the remaining 1 1/2 teaspoons oil. Spread 1/2 cup of the tomato sauce in the dish. Layer a third of the tortilla wedges on top and cover with a third of the beans. Repeat layering and then top with the remaining sauce. Sprinkle with the cheese and bake until browned (25-30 minutes).
7. Garnish with green onion to serve.