Spread a thin layer of sugar on a saucer. Run 1 lime wedge around rim of 2 margarita or martini glasses. Press rims into sugar on saucer to create narrow sugared edge on each glass.
In a cocktail shaker or small pitcher, combine tequila, mango nectar, lime juice and ice cubes. Shake or stir vigorously for 30 seconds. Strain equal amounts into each glass. Squeeze juice from 1 lime piece into each drink and drop lime piece in. Serve immediately.
Recipe courtesy of Sandra Lee Semi-Homemade Desserts, Miramax Books, 20