- Combine the water and sugar together in a small sauce pan and bring to a boil for about 1 minute.
- Remove from the heat and let cool.
- Shave off the rind of one lime using a micro plane grater and set aside.
- Juice the 2 limes and set aside.
- Remove the seeds from the watermelon and puree it in a blender or food processor.
- Add in the sugar mixture, lime juice and rind and blend until just combined.
- The mixture should be sweet and a bit tangy from the lime juice.
- Add more lime juice to taste.
- Pour watermelon mixture into a shallow metal pan and place on a flat surface in the freezer.
- Freeze for 2 hours then stir the mixture with a fork to fluff the ice.
- Repeat every hour until mixture is light and flaky.
- Serve in a glass goblet with a slice of lime or watermelon.
- To kick it up, you can drizzle with flavored vodka.