All ingredients ready? Let's begin!
The simple syrup: In a small saucepan over medium-high heat, bring the water and sugar to a simmer. Add the halved jalapeño pepper. Stir occasionally until the sugar has dissolved. Remove the pan from the heat, cover, and allow this to sit until cool. Remove the pepper halves and store the simple syrup in a sealed jar in the refrigerator until ready to use. You will have extra for more cocktails.
On a small flat plate, combine the smoked salt and chipotle powder. This will be the rim for the glasses.
Using a cocktail shaker or small pitcher, combine 1 ounce of the simple syrup, the mezcal, tequila, grapefruit juice, and lime juice. Shake or stir to combine well.
Coat the rims of 2 (8-ounce) old-fashioned cocktail glasses with lime from the wedge. Dip the rims of the glasses in the salt and chipotle powder.
Fill the glasses with ice. Pour the mezcal cocktail over the ice and top each drink with a good splash of sparkling water.
Serve right away. You can garnish with a slice of jalapeno or a twist of grapefruit peel.