1. Place the oysters in a bowl and cover with kitchen paper towel to absorb any liquid.
2. In a bowl, stir and mix well flour, red paprika, crushed black pepper, white pepper and kosher salt.
3. In a dish crack an egg, add a little water and beat well with a spoon.
4. Dredge the oyster in flour mixture, then in the egg mixture and again in the flour mixture.
5. Cook in a shallow frying pan with 1/2 cup hot oil until brown and crisp and drain on paper towel.
6. To assemble the sandwich, on a serving plate arrange 4 pieces of sourdough bread and drizzle over olive oil.
7. Cut the tip off a garlic clove, rub over the bread slices and broil or toast for a couple of minutes.
8. Cut the ends off a red onion make 3 slices and separate the rings.
9. On the toasted bread slices spread the cocktail remoulade sauce over one side of 2 breads.
10. Place the onion rings over the other two bread slices and the lettuce on the sauce coated slices.
11. Place the oysters over the onion rings and seal the sandwiches together.