Combine peach, plum, avocado, cilantro, lime juice, and salt in a medium-sized bowl. Place in fridge.
While salsa chills in the fridge, prepare your beans for the quesadillas. Combine beans, lime juice, and cilantro. Set aside.
Heat a medium skillet over medium-high heat. Add your olive oil once the pan is heated. (You’ll know your pan is ready when you add a drop of water and it sizzles and evaporates on contact.)
While the pan heats, assemble your quesadillas. On one side of the tortilla, layer bean mixture and feta cheese. Fold tortilla over.
Place quesadilla in the skillet. Cook until lightly brown or until cheese becomes slightly gooey. Flip the quesadilla.
Each side should take approximately 2-3 minutes to brown. Adjust heat as necessary to promote even heating.
Remove salsa from the fridge and serve with your quesadillas. Enjoy!