Sprinkle 2 teaspoons of fajita seasoning to ribeye and set aside
In a large skillet, heat 1 teaspoon avocado oil over high heat. Add onions and bell peppers and saute for 3 minutes, tossing occasionally. Reduce heat to medium and add 1 teaspoon of fajita seasoning. Saute for 6 minutes, until bell peppers are tender-crisp. Remove onions and peppers and set aside
Add remaining 1 teaspoon avocado oil to skillet. Add ribeye and cook for 4 minutes until seared on all sides. Return peppers and onions to skillet, toss to combine and remove skillet from heat.
Spray another large skillet lightly with cooking spray. Lay one tortilla in skillet; top steak and pepper mixture, and then sprinkle cheese on top. Cover with another tortilla. Take a flat pot cover and press down lightly on tortilla. Turn heat to medium and cook for 3 minutes per side, until tortillas are golden brown
Remove quesadillas from skillet and place on a flat surface. Use a pizza cutter to cut quesadillas into pieces. Serve immediately