1. In a large skillet, cook the ground beef over medium heat until browned and cooked through.
2. Stir in the pizza sauce, cook for an additional 10 minutes allowing the flavors to meld together and for the sauce to thicken. Remove from heat and set aside.
3. Heat a separate skillet or griddle over medium heat. Lightly brush one side of a flour tortilla with olive oil and place it oil-side down on the skillet.
4. Spread a layer of the meat mixture onto half of the tortilla, leaving a small border around the edge. Sprinkle a generous amount of shredded mozzarella cheese over the mixture.
5. Fold the tortilla in half over the filling, pressing down gently. Cook for two to three minutes on each side, or until the tortilla is crispy and the cheese is melted.
6. Remove the quesadilla from the skillet and place it on a cutting board. Let it cool for a minute before cutting it into wedges.
7. Repeat the process with the remaining tortillas and filling.