To make the tartar sauce, place the egg yolk, mustard, and lemon juice in a food processor or blender. Pulse to combine.
With the processor running, slowly add the oil in a steady stream. The mixture will become thick and emulsified. Add the capers, onions, pickles and their juice, parsley, lemon zest, and Tabasco and pulse to combine.
Remove to a small bowl and set aside, refrigerated.
To make the cornmeal flour, combine the flour, cornmeal, and seasonings in a medium bowl. Set aside.
To panfry the oysters, dredge them in the seasoned cornmeal flour. You can leave them in the bowl of flour until you are ready to panfry them. Shake off any excess flour right before frying.
Set up your sandwiches so they can be assembled as soon as the oysters are fried.
Split the French bread rolls lengthwise. For each sandwich, spread the tartar sauce generously on both sides of the bread. Line the top half of the roll with lettuce leaves.
You will need to use two or more non-stick sauté pans or a large sauté pan. Cover the bottom of each sauté pan with a thin layer (1/8 inch) of peanut oil. Over high heat, heat the oil until very hot.
Fry the oysters in the hot oil on both sides until golden brown and firmed up, about 4 minutes total. Drain the oysters on paper towels.
ON THE PLATE: Place 6 fried oysters on the bottom half of each roll. Put the lettucelined half on top to form a sandwich. Serve immediately.