Cucumbers add a welcome crunch to this refreshing summer salad of cubed watermelon, fresh herbs, and crumbled feta cheese. You can replace the fresh mint with basil if you prefer, or use a combination of both herbs. A personal-sized seedless watermelon is just the right size for this salad, but you can also use pre-cut melon or a portion of a larger watermelon. Be sure to dress the salad right before serving it to prevent the melon and cucumbers from watering down the vinaigrette.