Add rhubarb and sugar to a small pot, and fill pot with just enough water to cover the rhubarb. Bring to a boil, then lower heat to medium. Cover, and simmer until the rhubarb stalks begin to fall apart.
Strain sugar-water off of the rhubarb into a container, reserving rhubarb for another recipe if desired. Allow rhubarb syrup to cool to room temperature. (If desired, put syrup in the fridge to speed cooling process.)
Frozen Strawberry Rhubarb Margaritas:
Add all margarita ingredients to a blender and blend until smooth.
Optionally, rub the rim of your cocktail glasses with a lemon or lime wedge. Roll the edge of the glass in sugar to coat.
Pour frozen cocktail mixture in 2 large margarita glasses or 4 smaller stemmed cocktail glasses.
Notes
Makes 4 small cocktails, or 2 cocktails served in large margarita glasses. Double recipe to make a pitcher of margaritas.*Faster Cook Time: The Rhubarb Simple Syrup can be made ahead of time to shorten the recipe time to 5 minutes.