When I cook my chicken I usually simmer several legs quarters at a time with garlic, onion, cumin and chili powder. I shred the chicken and freeze what we don't use, which is good when you need a plan "B" supper. Strain and save that broth! It is a wonderful addition to white chicken chili or a pot of beans.
To put together the quesadillas, I saute onion slivers until almost done and toss in the spinach. Cook until wilted. Brush flour tortillas with a bit of butter. Layer 1/2 tortilla with chicken, spinach and onions and your choice of grated cheese. Fold wrap over chicken filling and cook over medium low heat until cheese is melted and tortillas are brown. Serve with salsa. Plan 'B" is good!