Arrange the watermelon on a large platter or individual plates. Sprinkle the crumbled feta on top, followed by the torn mint leaves.
In a blender, combine the ingredients for the dressing and blend until smooth. Alternatively, you can chop up the jalapeno and whisk it together with the other ingredients in a small bowl. Pour the dressing over the salad. Garnish with mint leaves. Serve and enjoy.
I like to chop the watermelon a few hours before serving so that it can sit in the fridge and get cold.
Sub basil or cilantro for fresh mint if desired.
This salad is best served right away, and leftovers do not keep well.