Rub the lime wedge over the rim of a small wine glass. Rub the glass rim in the salt crystals to coat entire rim. Put ice cubes, tequila, cointreau and lime juice in a cocktail shaker and shake for 15 seconds. Carefully strain the mixture into a wine glass. Cut a long, narrow, thin sliver of peel from a full cucumber and skivver it around the toothpick in a serpentine fashion and add to drink for decoration.