Move oven rack to lowest position; heat oven to 400°F. Spray 1 side of 4 tortillas with cooking spray. On large cookie sheet, place tortillas, sprayed sides down, overlapping in center so tortillas do not hang over edge of sheet. Top evenly with bacon, pineapple, cheese and remaining tortillas. Spray tops of tortillas with cooking spray. Place another cookie sheet on top of tortillas; press down.
Bake on bottom oven rack 8 to 10 minutes or until bottom tortillas are golden brown. Turn cookie sheets and quesadillas over. Bake about 5 minutes longer or until bottoms are golden brown and cheese is melted. Cut into 8 small wedges; serve warm with salsa.