Working in batches, puree the kimchi with the tomato juice, Sriracha, Worcestershire and vinegar. Set a fine-mesh strainer over a bowl and strain the kimchi puree, pressing gently on the solids to extract as much juice as possible; you should have 6 cups of kimchi-Mary mix. Discard the solids or reserve them for another use. Chill thoroughly, then season with salt and pepper and stir in the vodka. Serve over ice, garnished with mint sprigs or shiso leaves.