Adapted slightly from Ari Kolender of Leon's Oyster Shop (Charleston, SC) via Bon Appetit, July 2015.
If you don't want to plate the salad like this, you can use 1 cup cubed watermelon, which is much easier than getting cross sections of the watermelon, and then cutting circles out of that.
This serves about 8 as an appetizer with a serving size similar to what's pictured, or about 3-4 for lunch. Calorie count is calculated for 8 servings.