Prepare Rim (optional): Use a lime wedge, to slightly wet the rim of the glass. Then, delicately press the edge of the glass into the surface of a plate filled with Tajin or chili salt.
Add Ice: Fill the glass with ice cubes. Give it a stir to chill it and set it aside.
Add Agave Syrup: Take the shaker and pour in ½ ounce of agave syrup.
Add Lime Juice: Add 1 ounce of freshly squeezed lime juice.
Add Pineapple Juice: Measure and pour 3 ounces of pineapple juice into the shaker as well.
Add Mezcal: Finally, add 2 ounces of Mezcal to the mix.
Shake Well: Fill the shaker with ice, close it, and give it a good shake (10-15 seconds).
Strain: Take the Highball glass and use the cocktail strainer to remove any excess water inside. Then, use the cocktail strainer to strain the drink into the ice-filled glass.
Garnish: Garnish with a pineapple slice and serve immediately.