In whatever amounts you'd like, you'll need:

watermelon

avocado

feta

radish (optional)

red onion, chopped or sliced

mint, sliced or torn

chives, chopped

salt & black pepper

* I listed the ingredients in order of amount used, starting with the most prominent ingredient

You just cut the first four ingredients into rough one inch cubes, assemble them in any rectangular pattern you enjoy, sprinkle the herbs and red onion on top and finish with salt and pepper.