To salt the rim of a glass, rub a fresh cut wedge of lemon or lime around the rim. Keep a shallow tray about 1 cm (3/4 inch) deep with salt, and invert the glass and dip gently into the salt. Move the glass gently from side to side, but do not spin quickly or the salt will simply absorb the citrus and fall off the glass. Use rock salt or sea salt for the absolute best in flavor.