Do you ever feel like you're the last person to catch on to a trend? I've been reading about people combining watermelon and feta to make a salad for years now, and only did it myself last night for the first time.
The contrast between the salty feta and the sweet watermelon is dynamite. I through in some chopped parsley, Hawaiian Haleakala sea salt (it's an earthy red), freshly ground black pepper and some olive oil. And voila! Done!
I can see using some mint in there as a great addition too.