Heat the avocado oil in a skillet over medium heat. Add the onion and cook 3 minutes. Add the garlic, cumin, chili powder, chipotle and oregano and stir for 30 seconds until fragrant.
Add the black beans, lime juice and salt. Mash with a fork until thick and mostly smooth. Scrape into a bowl and wipe out the pan.
Spread the beans over 2 tortillas, top with cheese, then the remaining tortillas.
Add a little avocado oil to the pan over medium heat. Cook each quesadilla 2 to 3 minutes per side until golden and the cheese melts.
Stir the pico ingredients together. Slice the quesadillas into wedges and top with pico.