When I went to clean the pan that was used to sear the watermelon I realized that it was full of juice. Being me I was unable to resist sticking in a finger and giving it a taste. They were delicious. We just happened to have finished cleaning a batch of spot prawns from the farmer's market and I immediately reached for a few. I put them in a small container with the watermelon jus, some thin slices of jalalpeno and an extra shot of lemon juice. Ten minutes later we had a new twist on ceviche that tasted better than any version we'd ever had before. Just goes to show you that sometimes just using what's at hand will yield incredibly delicious results. Keep your eyes open and your palate ready.