In a large mixing bowl, use a hand mixer or stand mixer on medium speed to combine butter and sugar. Add the flour and salt; mix on medium speed. Add egg yolks and lime juice; combine, with mixer on low speed. Fold in lime zest.

Use a cookie scoop or wet hands to form dough into approximately 24 round cookies and place them on a parchment-lined baking sheet, leaving at least an inch of space between each cookie. Place in freezer to set for 30 minutes.

Preheat oven to 325°F.

Bake cookies for 14–16 minutes, until the outer edges start to brown. Allow the cookies to cool completely before adding glaze.

Whisk together powdered sugar, tequila, lime zest, and lime juice in a medium bowl until smooth and thick. (Don’t be tempted to add more liquid; the glaze will be very thick, but that’s the perfect consistency.)

Scoop glaze evenly onto centers of cookies (about 3/4 teaspoon per cookie). Spread glaze over the cookies using the back of a spoon, leaving a 1/4-inch border around the cookie edge. Garnish with flaky sea salt, sugar, lime zest, and/or Tajín, as desired. Let cookies stand until the glaze hardens, about 30 minutes.

Store cookies in an airtight container; they will last about a week at room temperature, 10 days in the refrigerator, and up to 3 months in the freezer.