Slice the flank steak into thin strips against the grain and place in a small bowl.
Toss the steak with chili powder, smoked paprika, cumin, sea salt, and black pepper until evenly coated.
Heat the olive oil in a large non-stick skillet over medium-high heat.
Add the steak strips to the skillet and sear for 2-3 minutes until browned, then remove and set aside.
In the same skillet, sauté the sliced bell peppers and onions for 3-4 minutes until they are tender and slightly charred.
Wipe the skillet clean and place the tortilla in the center over medium heat.
Sprinkle half of the cheese on one side of the tortilla, then layer on the cooked steak and vegetables.
Top with the remaining cheese and fold the tortilla in half.
Cook for 2 minutes per side until the tortilla is golden brown and the cheese is completely melted.
Remove from heat, open slightly to drizzle with lime juice and sprinkle with cilantro, then slice into wedges and serve.