Use leftover watermelon to add sweet flavor and fun color to this lime drink. If you like your watermelon with a sprinkle of salt, try this cocktail with a salt rim instead of sugar.
Place watermelon in a single layer on a baking sheet. Freeze 4 hours or until firm.
Coat rims of cocktail glasses with lime juice; dip in sugar.
Process frozen watermelon, tequila, and next 4 ingredients in a blender until slushy. Pour into glasses. Garnish, if desired.
*1/2 cup orange or apple juice may be substituted for tequila.