I have seen, although have never done this. Peel the outer green and julienne or thin slice watermelon rind and use in a stir fry.
I like Watermelon Pickles. I wish I could make Crisp watermelon pickles like my Grandmother's. I think she used Lye or some Galvanized Aluminum
product which helped make them crispy and took 3 days or week after changing the brine or Double Boiled or something. Some method we probably wouldn't use today.
Plus she set them in a crock in her basement with its single overhead light and creaky stairs. So the process seemed Mysterious. They always turned out Crisp, sweet and spicy. Funny. She made lots. But only gave them out in Small jars. And the irony, is, of course, watermelon gives so much to use.