Combine 2 teaspoons ground cumin, the chili powder and 1 teaspoon salt. Cut shallow crosshatch cuts into both sides of steak for entire length of steak.

Rub spice mix all over both sides. Place in a ziploc bag.

In a small bowl whisk lime zest, lime juice, 1/4 C. olive oil, Worcestershire, and half the garlic. Reserve 2 Tbsp. of the marinade and pour the rest into the bag with the steak. Seal and toss to coat. Refrigerate for at least 4 hours. Massage every now and then to redistribute marinade.

Heat 2 Tbsp. olive oil in skillet over medium-high heat. Add onions and saute 3-4 minutes until soft and translucent. Add in bell peppers and saute another 3 minutes.

Reduce heat to medium, add the remainder of garlic and cumin and salt to taste. Cook stirring often until peppers are soft and beginning to caramelize. 5-8 minutes.

Pour in the 2 Tbsp. reserved marinade. Stir in half the cilantro. Salt to taste and remove from heat and keep warm.

In a smoking hot dry pan blister tortillas on both sides. Place in an oven on very low heat to keep warm.

Remove steak from ziplock bag and pat dry with paper towels. Heat a large skillet over medium-high heat and add 1 Tbsp. olive oil. Cut steak and work in batches if your skillet is not large enough. Cook steak to your liking. 3-4 minutes per side for medium rare.

Remove to cutting board. Cover with foil and let sit 10 minutes. Cut across the grain into thin strips.

Tip remaining juices from pan over cut steak, and sprinkle with remaining cilantro.

Mix all white sauce ingredients together.

Sprinkle juice of 1/2 lemon over sliced lettuce, add salt.

Assemble fajitas. Place steak in tortilla and top with tomatoes, onions and peppers, lettuce and jalapeños if desired. Drizzle white sauce over top.