In a cocktail shaker, muddle the lime, cucumber and mint.
Add the syrup and vodka with plenty of ice, and shake until chilled.
Strain over ice into a Collins glass, and top with soda water. Serve with a cucumber wheel for garnish.
*Honey-hibiscus syrup: Bring 1/2 cup of honey and 1/2 cup of water to simmer, stirring to incorporate.
Remove from heat, add 1 hibiscus tea bag, and let cool.
Remove the tea bag and store in the refrigerator for up to a month.