Place the meat in a shallow baking dish and rub it with the garlic. Mix the tequila, lime and orange juices, the orange zest, Cholula hot sauce, vinegar, brown sugar, and pepper in a small bowl. Whisk in 1/4 cup of oil and pour the marinade over the meat.
Press 1 1/2 tablespoons of cilantro onto each side of the meat in an even layer. Cover the baking dish with plastic wrap and refrigerate for a few hours or overnight, turning the meat occasionally.
Place the scallions and red peppers in a bowl and toss them with 2 tablespoons of olive oil, the oregano and some salt.
Remove the meat from the marinade and pat dry with paper towels. Season it with salt.
In a grill pan over medium-high heat, place the meat and the vegetables and cook 3-4 minutes per side, depending on the desired doneness. Transfer the steak to a cutting board, cover loosely with aluminum foil and let it rest for 5 minutes.
Meanwhile, heat a medium skillet over medium-high heat. Add a tortilla and warm for 10 to 15 seconds. Flip the tortilla over and continue to warm until the tortilla is pliable and heated through, about another for 10 to 20 seconds. Place on a plate, cover with a kitchen towel, and set aside; repeat with the remaining tortillas. (or warm the tortillas in the microwave: stack them on a plate and cover with a damp cloth; microwave for 30 seconds and keep them covered until you’re ready to serve).
Cut the steak into thin slices against the grain and serve with the warm tortillas, the scallions, peppers and some avocado slices. Pass the remaining cilantro, lime wedges and Cholula hot sauce to season to taste.