I have been intrigued by this Bánh Mi craze of Vietnamese sandwiches, and pickled vegetables are one of the main condiments used in a bánh mi. The slaw is typically carrots and daikon radish, which is what I have used here. But you can use anything you like, such as cucumber, all carrot, red radishes, etc.
Try it here: http://www.threeolivesbranch.com/spicy-vietnamese-pickled-vegetables/