In a small saucepan, combine both vinegars, sugar, salt and lemon juice. Place over medium heat and stir until sugar is dissolved. Let cool 10 minutes.
Place celery seeds, cucumbers, Vidalia onion, and red onion in a large bowl.
Pour vinegar mixture over cucumbers. Cover and refrigerate at least 12 hours.
Notes
These Pickled Cucumbers and Onions will keep refrigerated for 3 to 4 weeks.