In a small pot on medium high heat combine the sugar and water, bring to a boil, then lower heat and simmer for 5 minutes. Let cool completely.
When the syrup has cooled had the strained lime juice and zest, whisk to combine. Pour into a freezer safe bowl. Place in the freezer for approximately 1 hour (may be more or less time depending on your freezer).
Remove bowl from the freezer and with a fork break up the ice and mix to combine. Repeat 3-4 times or until the mixture is slushy. Serve in a tall glass with a spoon.
ICE CREAM MAKER GRANITA
Follow the same steps for the freezer method, but instead of pouring into a bowl pour into the ice cream maker and churn according to manufacturer's directions, 25-30 minutes or until mixture becomes compact and creamy. Enjoy!