Preheat a large skillet or griddle over medium-high heat. If using a Blackstone griddle, preheat it according to the manufacturer's instructions.

In a bowl, combine the olive oil, garlic powder, onion powder, smoked paprika, salt, and pepper. Rub this mixture all over the flank steak.

Place the seasoned steak on the hot skillet or griddle. Cook for about 4-5 minutes on each side for medium-rare, or until desired doneness. Remove from heat and let it rest for 5 minutes before slicing thinly against the grain.

In the same skillet, add the sliced bell peppers and onions. Sauté for about 3-4 minutes until they are tender and slightly caramelized. Remove from heat.

Lay one tortilla on the skillet or griddle. Sprinkle ½ cup of shredded cheese on one half of the tortilla. Top with a portion of the sliced steak and sautéed vegetables. Fold the tortilla over to cover the filling.

Cook the quesadilla for about 2-3 minutes on each side, or until the tortilla is golden brown and the cheese is melted. Repeat with the remaining tortillas and filling.

Slice each quesadilla into wedges and serve warm with your favorite dipping sauces.