Step 1

Heat olive oil in a skillet over medium-high heat; saute mushrooms and onions until lightly browned, about 1 minute. Add black beans, cilantro, salt, and pepper; saute until mushrooms and onions are lightly browned, 2 to 3 minutes more.

Step 2

Place tortillas in a clean, dry skillet. Evenly distribute mushroom mixture onto 1 half of each tortilla. Top filling with mozzarella cheese and lime juice; fold each tortilla over filling. Turn burner to medium heat and cook until quesadillas are browned and crispy, about 2 minutes per side. Cut into wedges and serve with salsa.