This elegant beverage is a fizzy, slightly tangy nonalcoholic option for a brunch menu (or any spring or summer party).
In a medium, nonreactive bowl, combine cucumber, sugar, mint, lime zest and salt; stirring well to mix. Refrigerate, covered, at least 6 hours or up to 24 hours, stirring occasionally. Set a fine-mesh sieve over a bowl and strain the syrup, pressing on the solids before discarding them.
Stir vinegar into sugar syrup. Pour the mixture into a glass jar and chill until ready to use. To make the soda, combine 1 part syrup to about 3 parts chilled club soda, or adjust to your liking. Serve with slices of cucumber and/or wedges of lime.