Combine first 7 ingredients in a large bowl. Pour Buttermilk-Coconut Dressing over grapefruit mixture, tossing to coat. Cover and chill 1 hour.
Arrange arugula evenly on 6 salad plates. Toss grapefruit mixture, and place on arugula using a slotted spoon. Garnish, if desired.
from their cookbook,The Lee Bros. Southern Cookbook