In a medium saucepan, combine the lime juice, lemon juice, water, pineapple juice, sugar, lime zest and lemon zest. Bring to a boil over medium heat, and cook, stirring, until the sugar dissolves. Remove from the heat. Cool to room temperature and strain out the zests. (Can be made in advance and keep in a covered container in the refrigerator.)
Chill the margarita glasses in the freezer for 30 minutes. Place the coarse salt in a shall dish or saucer. Wet the rim of each with a lime wedge and dip the glass into the salt to coat.
In a cocktail shaker, combine the cooled citrus syrup with the ice, tequila and orange-flavored liqueur. Shake until frothy and well chilled, at least 1 minute. Strain into the prepared glasses and garnish each with a lime wedge.
Yield: 4 to 6 servings