I tend to think about this salad more in the summertime, but there's absolutely no reason not to serve it at other times. Use an English cucumber, and slice it paper-thin with a processor if you've got one. I did this one by hand, and my slices are a bit thicker. I used shallots instead of the more traditional red onions, and doused it all with oil and vinegar. Sprinkle with sesame seeds just before serving.