Cool and crisp: a choice complement to the Slow Cooker Red Beans and Rice. Try varying the slaw by adding slices of Granny Smith or Pink Lady apples to give it a slightly sweet and sour flavor and a crunchy bite.
Combine first 4 ingredients in a large bowl, stirring with a whisk until sugar dissolves. Add coleslaw and onions to vinegar mixture; toss to combine. Serve chilled or at room temperature.