In a small bowl combine the chili powder, cumin, garlic powder, oregano, paprika, salt, pepper, and cayenne pepper. Mix well.
Rub 3/4 of the spice mixture all over the pork and let it sit for 20 minutes.
Meanwhile, heat 1 tablespoons of olive oil in a medium skillet. Add the peppers and onions and saute for 7-8 minutes or until softened. Sprinkle with the remaining spice mixture and mix well.
Heat the other tablespoon of olive oil in a large skillet over medium heat. Add the pork flank steak and cook for 2-3 minutes per side or until cooked through.
Remove from heat and let rest for 2 minutes.
Thinly slice the pork.
Fill the tortillas with sliced pork, peppers, and onions.