In a bowl, combine apricots, orange peel, and orange juice; let stand until apricots are softened (about 10 minutes).
In a food processor or blender, combine apricot-juice mixture, ricotta cheese, honey, and coriander; whirl until smoothly pureed. (At this point, you may cover and refrigerate for up to 2 days.)
Arrange 6 tortillas in a single layer on 2 or 3 lightly oiled large baking sheets. Spread tortillas evenly with cheese mixture, covering tortillas to within 1/2 inch of edges. Evenly cover cheese mixture with pineapple, then top each tortilla with one of the remaining tortillas; press lightly.
Bake in a 450 degrees F oven until tortillas are lightly browned (7 to 9 minutes), switching positions of baking sheets halfway through baking.
Slide quesadillas onto a board; cut each into 4 to 6 wedges. Arrange on a platter and garnish with mint sprigs, if desired.