Bursting with sweet syrup, sour cherries impart a vivid fruit flavor to this retro-style cocktail. Curls of lemon zest add a bit of zing to the whiskey's hints of rich oak.
Place cherries in a heatproof bowl. Stir water and sugar in small saucepan to dissolve sugar. Bring to a boil, and pour over cherries. Let cool completely. Cover and refrigerate overnight.
Drain cherries, reserving syrup. Thread 4 cherries onto each of 6 skewers. Make 3 drinks at a time: Pour 6 tablespoons whiskey, 3 tablespoons kirsch, and 4 1/2 teaspoons reserved syrup in a cocktail shaker 3/4 filled with ice. Shake and pour into chilled glasses. Garnish each with a skewer and 2 to 3 strips lemon zest. Repeat for the second batch.