With three sweet items in this salad, you don’t want to use sweet vinegar. Lime juice, mint and feta provide a nice contrast that will keep this from being cloyingly sweet. Alternately, you could go with cilantro, Tajin and Cotija cheese for a Mexican vibe. You can use watermelon or any muskmelon for this recipe.
Bake 3 beets at 350 in foil or boil them until fork-tender. Allow to cool, then peel and cut into small cubes.
Finely slice red onion to make 1/4 C. Macerate in the juice of 1 lime.
While the beets are cooling, dice 1 large or 2 medium tomatoes, preferably an orange or yellow variety. Toss in a bowl with 1 t. salt and let sit for 5 minutes, then add 2 T. olive oil.
Cut a melon or watermelon in half and remove seeds if it has them. Cut one of the halves in 1″ thick slices, then remove the rind and cut the melon into cubes. You want about 1.5 Cups worth.
Toss all these ingredients together. Add 1/2 C. roughly torn mint leaves and 1/2 C. crumbled feta cheese.
Taste and add more lime juice, salt or feta to taste.