Sear tomatillos and onion for 4 to 5 minutes, then remove from heat.
In a food processor, combine seared tomatillos and onions with garlic cloves, cilantro, avocado, lime juice, jalapeƱos, and salt. Blend until smooth.
Transfer the salsa to a bowl and set aside.
**Make the Carne Asada:**
In a large bowl, whisk together olive oil, orange juice, lime juice, soy sauce, white vinegar, smoked paprika, cumin, oregano, salt, garlic powder, onion powder, cayenne, and black pepper to make a marinade.
Add flap steak to the marinade, ensuring it's evenly coated. Let it marinate for at least 30 minutes or overnight for best results.
Preheat skillet or grill over high heat.
Sear the steaks until browned on both sides, about 3 to 4 minutes per side.
Slice the steak into small cubes or thin strips against the grain.
**Assembly:**
Take a toasted telera roll and spread refried beans on the bottom.
Layer on the steak, Oaxaca cheese, cotija cheese, lettuce, avocado, white onion, cilantro, sour cream, and tomatillo salsa.
Seal the sandwich and enjoy!
Notes
For melty Oaxaca cheese, broil it in the oven before adding other toppings.
Customize your torta with your favorite toppings like tomatoes or pickled jalapenos, or skip ingredients you don't like. The possibilities are endless!