Make simple syrup. In a small saucepan combine sugar, water, cranberries and mint and simmer, uncovered, until cranberries pop and release their color and flavor, about 5 minutes. Strain into a glass jar and cool to room temperature then refrigerate until ready to use up to 7 days.
In a cocktail shaker filled with ice add vodka, cranberry juice, lime juice and bar syrup.
Shake to chill then pour into a tall glass.
Top with soda and garnish with mint leaves and lime wheels.