In a small bowl, mix together the lime zest, chili powder, ground cumin, paprika, dried oregano, garlic powder, onion powder, cayenne pepper, and salt and pepper. Place the flank steak in a small baking dish and sprinkle both sides with half of the seasoning, rubbing to fully cover. Pour half of the lime juice over the meat and cover the dish, letting the meat marinate at room temperature for 45 to 60 minutes (you can marinate in the refrigerator overnight, but let it come up to room temperature 1 hour before cooking).

When ready, heat a large cast iron pan or heavy bottomed skillet over medium heat. When hot, add the flank steak and cook for about 6 minutes. Flip and cover with a lid. Cook an additional 6 minutes. Remove and let the steak rest on a cutting board. Cover with aluminum foil until ready to slice.

Meanwhile, wipe the pan out as necessary. Add the olive oil and heat until runny. Add the peppers and onions and cook 8 to 12 minutes, or until desired tenderness. Add the remaining seasoning and stir to fully coat the veggies. Pour over the remaining lime juice and continue to cook about 30 to 60 seconds to let the lime juice steam off. Remove the pan from the heat.

Slice the meat into desired sizes, cutting against the grain.

Place romaine leafs on each plate then fill with meat topped with vegetables and desired accoutrements: cheese, sour cream, avocado slices.

Serve immediately! Enjoy!