Top 1 tortilla with layers of half each of the beans, sour cream, cheddar, tomatoes and avocados; cover with second tortilla. Cook in medium nonstick skillet on medium heat 1 min. or until heated through.
Turn quesadilla over carefully; top with layers of remaining beans, sour cream, cheddar, tomatoes and avocados. Cover with remaining tortilla. Cook 1 min. Carefully turn quesadilla over.
Cook 3 to 4 min. or until cheese is melted and bottom of quesadilla is golden brown.