tall narrow glass, preferably widening near the top
Place several large ice cubes in glass. Cut 8 - 10 thin slices of cucumber and distribute these on top of the ice cubes. Pour vodka over ice and cucumbers, filling 1/3 - 1/2 of glass (depending on how much it widens near the top). Make sure you use as clear and flavorless a vodka as you can find - this is not a drink to cover up the pungent taste of rotgut - I've been using Smirnoff. Furthermore, using ice-cold vodka ensures the drink mixes itself. Next, pour on a tiny splash of cranberry juice; the red from this should sink to the bottom. Fill remainder of glass with sparkling water (make sure it's not flavored - I've been using Pellegrino). Finally, put a dab of honey on the end of a flat knife and rub gently around the rim of the glass. If all goes well, you'll have a refreshing summer drink. Ideally, the main taste should be of cucumbers, with the water and vodka acting as a mere vehicle for this delicate flavor. Resist the urge to use too much vodka or too much honey. The cranberry juice really only serves to counterbalance the vodka flavor, ideally one shouldn't actually taste it (this is why only a splash is required). Enjoy.