Onion and watermelon? That sounds like a combination for the courageous! I don't think my brain would let me combine onion with a fruit. Although, It sounds summery and sort of fresh. I've not come across this dish before so hope to hear how it goes when you manage to "cook" it. Good luck.
Isn't it funny how people put things together that other people find off-putting? I know what you mean though, onion and watermelon doesn't seem like a match made in heaven although I have it on good authority that it is very tasty, this salad, so I'm willing to risk it.
Becca 🌷