Combine the fruit powder seasoning, salt and sugar in a shallow dish. Pour 1/4 cup water into a second shallow dish. Dip the rim of your glasses into the water first, and then into the fruit powder mixture to rim the glass. Place large ice cubes into a cocktail shaker, and then add the tequila, lime juice, raw sugar and orange liqueur. Shake well. Spoon the tamarind puree into the bottom of each glass, fill with ice cubes and pour the margarita mixture over. Serve with lime wedges.