2 ounces blanco tequila
Juice of 1 whole lime
½ ounce triple sec, preferably Cointreau
Salt for rim
Lime wedge, for garnish
Place some salt on a small plate. Rub rim of an old-fashioned or rocks glass with lime (reserve for serving); dip in salt. Fill with ice and set aside.
Combine tequila, lime juice, and simple syrup in a cocktail shaker. Fill shaker with ice, cover, and shake vigorously until outside of shaker is very cold, about 20 seconds.
Strain cocktail through a strainer or a slotted spoon into reserved glass. Garnish with lime wheel.