Combine the jalapeño slices with the honey and gently muddle to release heat and aroma without breaking down the peppers. Let stand for 1 minute to infuse.
Lightly coat the rims of two rocks glasses with honey, then dip into Tajín, forming a thin, even crust. Chill the glasses.
Fill a cocktail shaker halfway with ice. Add the jalapeño-honey mixture, lime juice, tequila, and orange liqueur. Shake vigorously until well chilled, about 25 to 30 seconds.
Fill the prepared glasses generously with fresh ice. Strain the cocktail evenly between the glasses.
Garnish with a fresh jalapeño slice, if desired, and serve immediately.