Thinly slice the flank steak against the grain into bite-sized strips.
Slice the bell peppers and red onion into thin strips.
In a small bowl, combine the cumin, garlic powder, sea salt, and black pepper, then toss the steak strips in the seasoning.
Heat the olive oil in a large non-stick skillet over medium-high heat.
Add the steak to the skillet and sear for 2-3 minutes until browned, then remove and set aside.
Add the peppers and onions to the same skillet and sauté for 4-5 minutes until tender and slightly charred.
Wipe the skillet clean and place the tortilla in the pan over medium heat.
Sprinkle half of the cheese on one side of the tortilla, then layer on the steak and sautéed 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 fully melted.
Slice into wedges and serve immediately.