Use a chef's knife and cutting board to dice the watermelon into roughly 1-inch cubes and peel, pit, then slice the avocados into thin wedges.
4 cups watermelon, cubed
Transfer the cubed watermelon and sliced avocado into a large mixing bowl, gently tossing to combine.
4 cups watermelon, cubed
Crumb the feta cheese over the combined fruit, distributing evenly.
4 cups watermelon, cubed
Sprinkle a pinch of salt over the mixture and gently toss again to incorporate the seasoning.
4 cups watermelon, cubed
Transfer the salad onto a serving platter, arranging the pieces attractively, and serve immediately to enjoy the fresh textures and flavors.