- Add sliced steak to a small bowl and stir in teriyaki marinade. Cover and refrigerate for 30 minutes.
- Stir together sour cream and sriracha. Refrigerate until serving.
- Heat 1 tablespoon of olive oil in a skillet over medium heat and add onion and bell pepper. Sauté for 5-7 minutes, stirring occasionally. Transfer to a bowl.
- Drain and discard marinade, then add steak to skillet over medium-high heat. Sear steak for 5-6 minutes, stirring occasionally. Add to bowl with vegetables.
- Wipe skillet clean. Using half of the cheese, cover half of each tortilla and top with steak and vegetables. Top with remaining cheese. Fold the empty halves over and place first quesadilla on lightly greased skillet. Cook over medium heat for 3 minutes on each side. Repeat with second quesadilla.
- Slice quesadillas into triangles and serve with sriracha sour cream for dipping.