Preparation

• Put the tamarind pods or paste and the sugar in a large heatproof bowl. Cover with the boiling water. Let stand until cool, about 30 minutes. (If using pods, rub the pulp into the water with your fingers, and then strain over another bowl or into a pitcher to remove the seeds.) Add the tequila and lime juice.
• Put some Tajín powder on a small plate. Moisten the rim of each glass with a lime slice, and dip into the Tajín. Fill glasses with ice, then add the margarita mixture. Garnish each with a lime slice.