2 red bell peppers, cut into 2-inch-long matchsticks
1 medium onion, thinly sliced
1 teaspoon finely chopped sage
1 teaspoon finely chopped rosemary
Salt and freshly ground pepper
Six 8-inch flour tortillas
1/3 cup mayonnaise
12 green leaf lettuce leaves
In a sturdy resealable plastic bag, combine 1/4 cup of the olive oil with the Worcestershire sauce and 2 tablespoons of the vinegar. Add the flank steak. Seal the bag and marinate the meat at room temperature for 2 hours.
Heat the remaining 1 tablespoon of oil in a large skillet. Add the red bell peppers and onion and cook over moderate heat, stirring, until tender and browned, about 10 minutes. Add the remaining 2 tablespoons of vinegar along with the sage and rosemary and cook until the vinegar has evaporated, about 2 minutes. Season with salt and pepper.
Preheat the broiler and position a rack 8 inches from the heat. Remove the flank steak from the marinade. Season the meat with salt and pepper and broil for about 4 minutes per side for medium rare. Transfer the steak to a cutting board, cover loosely with foil and let stand for 5 minutes. Thinly slice against the grain.
Spread a tortilla with a thin layer of the mayonnaise and top with 8 to 10 slices of steak in a single layer. Season with salt and pepper, then add 2 lettuce leaves and 2 tablespoons of the pepper relish. Roll up the steak in the tortilla and seal the roll with a little mayonnaise if necessary. Cut off the ends to make a neat roll and cover with plastic wrap. Repeat with the remaining ingredients. Slice the rolls 3/4 inch thick and serve.
The filled rolls can be refrigerated for up to 3 hours. Slice them just before serving.