Heat the oil in a 12-inch skillet over medium-high heat. Add the peppers and onion to the skillet and sauté until vegetables soften, about 5 minutes, stirring occasionally. Add the shredded beef taco meat and cook until warmed through, about 4-5 minutes.
Meanwhile heat the flour tortillas over a gas flame for about 30 seconds each, or in the microwave.
In a different 12-inch skillet, melt the butter over medium heat.
Warm the beans in a small saucepan over medium heat.
Whisk the eggs in a medium bowl and add a splash of milk or water. Add a pinch of kosher salt and add to the skillet. Cook, stirring often with a spatula until the eggs are softly cooked.
Put a few spoonfuls of beef in the bottom of a tortilla and add some scrambled egg. Add some of the beans and then garnish with avocado, tomato and cotija cheese. Repeat with remaining tortillas. Serve with chopped cilantro and salsa if desired.
To make these tacos freezer-friendly, leave out the toppings (avocado, tomato, cotija cheese and cilantro – the salsa will be fine), and simply fold your tacos up like a burrito, wrap in foil, and place in a freezer-bag. To reheat, preheat your oven to 400 degrees, and place the tacos (still wrapped in their foil) in the oven. Bake for about 10 minutes.