Place first 4 ingredients in a medium sized bowl.
Pour lime juice over all and add lime zest.
Gently fold together being careful not to smash the watermelon
Add salt and taste for your preference.
Chill before serving.
This salsa kept really well in the fridge. We had it on chicken tacos one night, and shrimp tacos the next. It would also be wonderful served with chips or as a topping for fish. The possibilities are endless!