Serve this sauce with our Spiked Clams and Oysters.
Bring lime juice, zest, mint, sugar, and 1/2 cup water to a boil in a small saucepan. Remove from heat; cover, and let steep until completely cool, 20 to 25 minutes.
Pass lime-juice mixture through a fine sieve set over a bowl, pressing on solids to extract liquid; discard solids. (If not serving immediately, refrigerate in an airtight container up to 1 day.) Just before serving, stir in tequila.