How to Make It
In a saucepan, simmer the tamarind and water over low heat, stirring, until the pulp dissolves. Press the mixture into a shaker through a fine-mesh sieve. Add 1/2 cup of the tequila and the sugar; shake vigorously. Add ice to the shaker, then add 1/2 cup of lime juice, the Cointreau, the orange juice and the remaining 1/2 cup of tequila; shake well.
Pour the remaining 2 tablespoons of lime juice and the salt mixture into 2 bowls. Dip the rims of 4 old-fashioned glasses first in the lime juice and then in the salt mixture. Fill the glasses with ice. Strain the drink into the glasses and garnish with the lime wedges.
Tamarind pulp is available at Asian and Middle Eastern markets and specialty food shops.
Tamarind pulp is sold in a dense block that can be wrapped in plastic and refrigerated in an airtight container for up to a year. To reconstitute it, break off an inch or so of the block and submerge it in warm water for about 15 minutes. Press the softened pulp and liquid through a strainer over a bowl to separate the diluted pulp from the seeds and fibers. Don't confuse tamarind pulp with the less fresh-tasting tamarind concentrate that is sold pre-mixed in a jar.