In a mixing glass, muddle fresh mango, sage, and agave nectar 2-3 times. Combine remaining ingredients in a mixing glass. Shake well, strain over fresh ice. Garnish.
For the Cucumber-Chile Shrub:
Combine cucumber and sugar and let sit at room temperature until sugar dissolves and sugar turns into liquid, 24 to 48 hours. Add vinegar and let sit for additional 12 to 24 hours, depending on desired flavor. Strain out all solids.
Recipe by Tony Pereyra, Bar & Beverage Solutions, The Spirits in Motion