Mix together salt, sugar, and chipotle chili powder on a small plate. Run a lime wedge around rim of cocktail glass, dip into salt/sugar/chili mixture; fill glass halfway with ice.
Fill a cocktail shaker about ⅔ full with ice and add the tequila, grapefruit juice, lime juice, and simple syrup. Cover and shake vigorously for 15 seconds until chilled.
Strain the shaker into the prepared cocktail glass and top with club soda.
Garnish with a lime slice and grapefruit wedge, if desired.
Video
Notes
Omit simple syrup, if desired.
For a pitcher (8 servings): Stir together 2 cups tequila, 2 cups grapefruit juice, ½ cup lime juice, and 2-3 tablespoons simple syrup, or to taste. Refrigerate until ready to serve. Pour into prepared glasses, filled halfway with ice, and top with club soda (about 2 oz. per glass).