Fill a mule mug or rocks glass to the top with crushed ice or ice cubes.
Add the jalapeño tequila and lime juice. Top with ginger beer.
Garnish with a lime wedge and/or jalapeño slices.
Notes
In lieu of jalapeño tequila, you can use blanco tequila and a jalapeno simple syrup. Add 1 ounce of jalapeño simple syrup with the lime juice and tequila. Stir before adding the ginger beer.For a milder cocktail, use a less spicy ginger beer like Fever-Tree or Bundaberg.For an even spicier cocktail, try one of these options:
Use a super spicy ginger beer. Try Maine Root or Reed's Strongest.
Make your jalapeño tequila spicier. Try adding habanero or serrano peppers to make a spicier tequila infusion. (Same goes if you're using the jalapeño syrup method.)