Place watermelon chunks in a blender and blend on high for a few seconds until it becomes a juice.

Strain the blended watermelon in a mesh sieve into a cocktail shaker or pitcher filled with ice.

To make the honey simple syrup, mix together 1 tablespoon honey (or agave) with 1 tablespoon warm water so that the honey will easily mix into the margarita.

In the cocktail shaker or pitcher that you strained the watermelon juice into, add tequila, triple sec, lime juice and honey.  Mix until well-chilled.

To salt the rim, add a little lime juice or water on a small plate and add salt to another plate.  Dip the rim of each glass in the lime juice or water and then dip that into the salt.

Fill with ice and pour the shaken margarita into each glass.  Add blueberries, if desired, and enjoy!