Watermelon and Mint Salad

1 (5-pound) watermelon
1 Walla Walla Sweet onion
1/4 cup red wine vinegar (or lemon juice)
Salt and pepper, optional
1/2 cup extra-virgin olive oil
2 tablespoons chopped fresh mint
4 ounces feta cheese, crumbled (or tofu alternative)
6 whole mint sprigs

Cut the flesh from the melon and cut into bite size pieces, removing
and discarding the seeds, and set aside. Peel and slice the onion
into rings.

In a small bowl, combine the vinegar, salt, pepper, and whisk until
salt is dissolved. Slowly whisk in the olive oil, a few drops at a
time. Add in the chopped mint, taste, and adjust seasonings.
In a large bowl, combine the ingredients together.
To serve, divide salad among individual plates and garnish with mint
leaves.