For an extra layer of flavor, try grilling the watermelon cubes briefly before adding them to the salad. If you don't have fresh mint, a pinch of dried mint can be used, but fresh is highly recommended. The vinaigrette can be made ahead of time and stored in the refrigerator for up to 3 days. Be sure to shake well before using. Adjust the amount of honey in the vinaigrette to your liking, depending on the sweetness of the watermelon and orange juice.