Heat 1 tablespoon oil in a large skillet over medium-high. Add steak; cook for 5 minutes. Add spinach, cream cheese, feta, and olives; stir to combine and cook 2 minutes. Remove steak mixture and set aside.
Wipe pan clean with a paper towel. Spoon 1/3 cup of the steak mixture onto half of each tortilla. Fold tortilla over filling.
Add 1 1/2 teaspoons oil to pan. Place 2 quesadillas in pan; cook for 2-3 minutes on each side or until browned. Repeat with remaining 2 quesadillas.
Cut each quesadilla into 4 wedges. Serve with low fat yogurt.