Rim your glass with lime juice and dip in Tajín.
In a cocktail shaker, muddle the peeled clementines until juicy.
Add the jalapeño-infused tequila, Cointreau, lime juice, agave, and ice.
Shake well for about 15 seconds.
Strain into your prepared glass over fresh ice.
Garnish with a thin clementine wheel or a jalapeño slice if desired.