A couple of years ago I was working with Charlie Trotter's Catering around the Chicago area and a this salad popped up at several events during the summer. I am not saying that I have the top secret Trotters recipe, but you can see that it is simple enough to do without one. When you first read the ingredients it sounds odd but they really play well together to make a beautiful light refreshing salad that lends itself to a picnic or BBQ.
As is kind of normal with me there is no real recipe this salad contains:
Watermelon cut into a 1 inch dice
Fresh ground pepper
First dice your watermelon and Feta cheese and put those ingredients into a large bowl, then cut the fresh mint into a fine chiffonade and sprinkle on top. Poor on a little olive oil and toss. The olive oil helps all of the ingredients work together. Crack a little pepper on top then add a pinch of salt and you are ready to go.