Special equipment: brown paper bag; a food processor
Drain the oysters and place in a small bowl. Cover with 1 cup milk and let soak for 15 minutes. In a medium bowl, whisk together remaining milk, water, cayenne and eggs. Place the flour, cornmeal, black pepper, and salt into a brown paper bag, close and shake to mix.
In a large heavy-bottomed pot, pour enough oil to fill the pan halfway. Heat until a deep-frying thermometer inserted in the oil reaches 360 degrees F.
Drain the oysters from the milk. In batches dip oysters in the egg mixture then drop in the paper bag. Close and shake. Remove to a plate and repeat with the rest of the oysters. When oil is at 360 degrees F, fry oysters in batches. Do not overcrowd. Cook turning once until golden brown and cooked through, about 3 minutes. Remove to a paper towel. Repeat with remaining oysters.
To serve, cut sandwich loaves in half horizontally. Slather a generous amount of Spicy Remoulade Sauce on the inside. Place a lettuce leaf inside and fill generously with oysters. Squeeze fresh lemon juice over oysters just before serving.
Place all ingredients into a food processor and blend until smooth. Chill until ready to serve.