Preheat oven to 400 degrees.
Heat 2 tablespoons olive oil in a large oven-safe skillet over medium. Saute the onion and pepper until softened, about 5 minutes. Stir in the chipotle chili powder, smoked paprika, garlic, onion, oregano, cumin, and tomato paste until fragrant, about 1-2 minutes longer.
Pour in the beer, buffalo sauce, and drop in the butter. Season with a good pinch of salt and pepper. Bring to a simmer and cook until slightly thickened, about 10 minutes. If the sauce thickens too much, add another 1/4 cup of beer. Remove the pan from the heat and stir in the cilantro.
In a large bowl, combine the ingredients for the filling, including 1 cup of the cheese, until well mixed.
Warm the tortillas in the microwave under a damp paper towel for 20-30 seconds. Spoon 1/8 of the mixture into one of the tortillas and roll. Nestle seam-side down into the sauce. Repeat with the remaining tortillas and filling.
Sprinkle with the remaining cheese and transfer to the oven for 15-20 minutes until the cheese melts and the sauce bubbles. Serve with avocado, green onions, extra cilantro, and any other desired toppings.