- Use a juicer or blender to extract about 3/4 cup of fresh watermelon juice from the cubed flesh. Pour the juice into a mixing bowl. 
- Roll the lime on the countertop to loosen the juice, then cut in half and squeeze to extract fresh lime juice. Zest a small amount of lime peel with a microplane, then add both to the watermelon juice. 
- Chop the cilantro into small pieces and add it to the bowl with the watermelon juice and lime. 
- Add honey (if using) and salt to the mixture. Stir well with a spoon or spatula until the ingredients are evenly combined and the salt is dissolved. 
- Let the salsa sit for 5 minutes at room temperature to allow flavors to meld. The salsa should be bright, slightly pulpy, and vibrant in color with visible cilantro leaves and bits of lime zest. 
- Serve immediately as a refreshing accompaniment to grilled chicken or seafood, or chill for 15-20 minutes for a cooler, more infused flavor.