Combine all ingredients in a medium bowl. Mix well.
Taste salsa, then add additional salt and / or lime juice, if needed.
Serve immediately or refrigerate until ready to eat. Enjoy!
Notes
Recipe makes about 3 ½ cups. One serving is considered ½ cup.Watermelon releases lots of liquid after it's cut. If you don't eat this salsa right away, you may want to drain it a bit (and adjust the seasoning) before serving. This recipe is super flexible. Feel free to change it up by adding other fruit, tomatoes, cucumber, different herbs or peppers, black beans, etc. Find more tips in the information before the recipe. Make sure to wash your hands, knife, and cutting board thoroughly (and immediately) after handling the jalapeño.