Greek Quesadillas

large (10-inch) whole wheat tortillas

Olive oil

Fresh spinach leaves, chopped (about 2 cups)

Diced red onion (about ½ cup)

Roasted red peppers, chopped

Oven-dried tomatoes

Sliced black olives

Mozzarella cheese, shredded (about 1-1½ cups)

Crumbled feta cheese (about 2/3 cup)

Oregano (dried or fresh)

Red pepper flakes