There are numerous ways to muddle a cucumber wrong, but only one way to do it right, and "gently" is its mantra. When you muddle cucumber, you want its essence -- the esters responsible for its clean, mild taste -- to come through, not the remnants of flesh that result from pulverizing it. Peeling and seeding is often overlooked when muddling cucumbers; cucumber seeds and skin contain tannins, which impart an unwelcome bitterness to mixed drinks. For a delicate, yet highly aromatic, cucumber component in a cocktail, use a floral variety, such as Japanese or Persian cucumbers.
Rinse and dry the cucumber, then peel the skin from it. Slice the cucumber in half lengthwise and scoop out the seeds using a spoon. Discard the seeds.
Slice the cucumber into 1/4-inch-thick slices; you need about 10 to 12 seedless slices for each mixed drink. Place the cucumber slices in the shaker, along with any fresh herbs and other ingredients that require muddling.
Press the muddler gently into the cucumber slices while rotating your wrist. Press the cucumber against the side of the shaker as you twist your wrist.
Stop muddling the cucumber when you detect a strong cucumber aroma, about six or seven presses and twists of the muddler. Add the remaining cocktail ingredients and finish the drink as prescribed by the recipe.