Two of my favorite things in the world combined.  Perfect summertime refreshment.

1 teaspoon lime zest
½ cup water
½ cup sugar
3 tablespoons coarse salt
1 lime wedge
1 cup watermelon puree (recipe below)
2 tablespoons fresh lime juice
½ cup premium 100% pure blue agave tequila
2 tablespoons orange-flavored liqueur (Grand Marnier or triple sec)
1 cup ice

In a medium saucepan, combine the lime zest, water, and sugar. Bring to a boil over medium heat, and cook, stirring, until the sugar dissolves. Remove from heat.  Cool to room temperature and strain out the zest. You can make this in advance; keep in a covered container in the refrigerator.

Chill margarita glasses in the freezer for 30 minutes.  Place the coarse salt in a shallow dish or saucer. Wet the rim of the glass with a lime wedge and dip the glass into the salt, coating the top edge.

In a cocktail shaker, combine 2 tablespoons of the cooled lime syrup with the watermelon puree, lime juice, tequila, orange-flavored liqueur, and ice. Shake until frothy and well chilled, at least 1 minute. Strain into the prepared glass and garnish with a lime wedge.

To make the watermelon puree, remove seeds from fresh watermelon and cut into large chunks. Place in a blender and process until smooth and well pureed.