1. Heat the oven to 350°. Stack the tortillas and wrap them in aluminum foil. Warm in the oven for about 15 minutes.
2. In a large frying pan, heat 2 tablespoons of the oil over moderately high heat. Add the onions, peppers, and 1/2 teaspoon of the salt and cook, stirring occasionally, until browned, about 10 minutes. Set aside.
3. Light the grill or heat the broiler. Coat the steaks with the remaining 1 tablespoon oil. Sprinkle with the remaining 1/2 teaspoon salt and the black pepper. Grill or broil the steaks for 3 minutes. Turn the meat and cook to your taste, 2 to 3 minutes longer for medium rare. Let rest in a warm spot for 5 minutes. Cut the steaks diagonally across the grain into thin slices.
4. Roll the steak slices, onions and peppers, and Roquefort in the warm tortillas.
Variation: For a new-style Philly cheese steak, use the same filling, but put it in crusty rolls.
Wine Recommendation: Fajitas and merlot go together like chips and salsa. The wine's plum, chocolate, and herb flavors are a natural with steak and peppers, while its soft, velvety texture plays counterpoint to the fajitas' rough-hewn construction.