Cut 8 thin rounds from cucumber; set aside for garnish.
Chop remaining cucumber and place in blender with 1/4 cup (60 mL) water; puree until smooth. Strain through fine-meshed sieve; discard solids. In small bowl, stir together cucumber puree, cilantro, vodka, lime juice, Worcestershire sauce and salt to taste.
Just before serving, shuck oysters; reserving oyster liquid. Shake cucumber mixture in cocktail shaker with ice cubes; strain into 8 shooter glasses. Add an oyster and some reserved oyster liquid into each shooter. Garnish each with chili pepper and a cucumber slice.
For best flavour keep oysters, cucumber mixture and shooter glasses chilled.
Look for oysters that feel heavy in the hand and shells that are tightly shut. Don’t eat oysters that are already open even if they shut after being nudged. Store oysters in refrigerator with a wet towel draped over them so the shells don’t dry out.
Substitute vodka with gin or tequila.