Mix 1 tablespoon sugar with salt on a shallow, rimmed plate. Use lime wedge to wet rims of two 6- to 8-ounce glasses. Dip rims into sugar mixture.
Combine jalapeno and 1 1/2 teaspoons sugar in a cocktail shaker and muddle until sugar is dissolved and jalapeno is juiced. Add orange juice, mezcal, and lime juice to shaker, then fill with ice. Cover and shake until chilled, about 30 seconds. Strain into glasses to serve.