In a small saute pan, gently cook onions until soft. Add corn, black beans, chicken, lime juice, cilantro, salsa and cumin. Cook for approximately five minutes, until corn is soft. Remove mixture to a plate. Wipe pan down with a paper towel, leaving some oil in the pan. Assemble the quesadilla by spreading a thin layer of avocado on one wrap. Top with cheese and black bean mixture. Sprinkle with additional cheese. Add back to the frying pan (or put on a cookie sheet in the oven at 400 degrees) for 6 minutes or until cheese is melted. Using a pizza cutter, cut into quarters.