Use painters tape to two horizontal lines, leaving 3/4 of an inch in between.
Coat the 3/4 strip with simple syrup using a pastry brush. Dip the rim of the glass and coat it with Tajin
Fill the rocks glass with ice and set aside.
Add the Mezcal or sparkling water, cucumber jalapeno juice, lime juice, and simple syrup into the cocktail shaker.
Add ice to the cocktail shaker and shake well.
Strain the ice while pouring the ingredients into the rocks glass.
Garnish with a lime wedge and a fresh or dried pepper.
Notes
Mocktial version: Replace the mezcal or tequila with sparkling water. Avoid shaking the mocktail in a cocktail shaker due the carbonation in the sparking water. Instead, stir with a cocktail spoon to mix the ingredients.