Thread red onion onto toothpick with purple showing on top, then tomato, then cucumber. Use feta cube as a base for the appetizer by skewering the feta on the bottom; place on your platter.
Just before serving, whisk together a simple red wine vinaigrette to drizzle over the skewers. (Try not to get too much dressing on the tops of the toothpicks, where people will pick them up to eat them).
Notes
Prepare skewers several hours ahead, gently wrap and refrigerate. Add dressing right before serving.
Add kalamata olives for a complete Greek salad taste!