How to Make It
Combine Worcestershire, cumin, chili powder, oregano, lime zest, lime juice, garlic, 1/4 cup olive oil, and 1 teaspoon of the salt in a large ziplock plastic bag, and mix well. Reserve 2 tablespoons of marinade in a small bowl. Add steak to bag and seal tightly. Marinate in the refrigerator at least 4 hours or overnight, turning and massaging marinade into meat occasionally.
Heat 1 tablespoon of the oil in a large cast-iron skillet over medium-high. Add bell peppers, onions, and, if desired, jalapeño; cook, stirring often, until slightly softened and caramelized, about 5 minutes. Sprinkle with remaining 1/2 teaspoon salt. Add reserved marinade, and cook, stirring to scrape any loose brown bits from the bottom. Transfer bell pepper mixture to a platter, and cover with aluminum foil to keep warm. Wipe any extra juice from bottom of skillet, and return to medium-high.
Remove steak from marinade, allowing any excess marinade to drip off; discard marinade. Heat remaining 1 tablespoon oil in skillet over medium-high. Add steak; cook to desired degree of doneness, or 4 minutes per side for medium-rare. Transfer to a cutting board, and let stand, tented with aluminum foil for 5 minutes.
Slice steak, across the grain in 1/2-inch slices, and place on platter with vegetables; sprinkle with cilantro. Serve with tortillas, pico de gallo, and sour cream.