Make a simple syrup: In a saucepan, bring sugar and 1 cup water to a boil, stirring until sugar is dissolved. Stir in lemon zest and cool to room temperature.
Transfer syrup to a small pitcher and stir in 2 cups water, lemon juice and mint to make lemonade. Chill until cold.
Pour 1 part lemonade into each chilled beer glass. Add 3 parts beer and top off with sparkling water. Add a little Tito's vodka if you desire something with more of a kick.