From http://www.epicurious.com/recipes/food/views/Chilled-Watermelon-... , but the flavor profile would probably also make a great salad.

6 pounds yellow or red seedless watermelon, diced (9 cups)
2 tablespoons chopped fresh mint
1 tablespoon sugar
2 tablespoons fresh lemon juice
1 cup lightly sweet white wine (such as Riesling) or 3/4 cup water mixed with 1/4 cup sugar
1 teaspoon chopped ginger
8 teaspoons crumbled feta
1/4 cup sparkling wine (or sparkling water)

Combine 1 cup of the watermelon with mint and sugar in a bowl. Set aside. Blend remaining 8 cups watermelon, lemon juice, wine, and ginger in a blender until smooth. Let sit 1/2 hour. Strain soup; divide among 8 bowls. Top each with 1/8 cup reserved watermelon and 1 teaspoon feta.