In a bowl, whisk together olive oil, cider vinegar, orange juice, lime juice, Worcestershire sauce, cilantro, garlic cloves, chili powder, paprika, salt and pepper. Add the sliced mushrooms and onion to a large ziptop bag. Pour the marinade into the bag, seal tightly, and shake vigorously until the marinade thoroughly coats the mushrooms. Let the mushrooms soak in the sauce for 10 minutes at room temperature, or up to 24 hours in the refrigerator.
Make the guacamole. In a food processor, combine avocados, cilantro, mint, red onion, lime juice, and a pinch of salt. Blitz until desired smoothness. Pour into a serving dish or resealable container. Stir in mango chunks. Refrigerate until ready to serve.
When the mushrooms are finished marinating, heat 1 tablespoon of olive oil in a large skillet over medium heat. Remove mushrooms from the bag with a pair of tongs and spread into the skillet. Cook undisturbed for 8-10 minutes, turning once halfway through. Remove from heat.
Assemble the quesadillas! Warm tortillas in the microwave between damp paper towels for 30 seconds to render more pliable. Set one tortilla on a flat, clean surface. Spread 1/2 of the mushroom mixture atop. Sprinkle 1/2 cup of cheese. Set a second tortilla over the filling and press gently. Repeat.
Wipe skillet clean and heat 2 tablespoons olive oil over medium. Set one quesadilla into the pan and cook 3 minutes on one side, then flip carefully and cook 2-3 minutes on the second side until crispy and the cheese melts. Repeat with the second quesadilla.
Slice each quesadilla stack in half, and then into as many wedges as you'd like from there. Serve with mango guacamole, lime wedges, cilantro, and Greek yogurt or sour cream.