Heat oil to 360 degrees.
In a small bowl, combine buttermilk, egg, and hot sauce.
In a medium bowl, combine cornmeal, flour, and cajun seasoning.
Dip oysters in buttermilk mixture, then coat with cornmeal mixture. Drop into oil 6-10 at a time, being careful not to crowd.
Let oysters cook 2-3 minutes (depending on size) and pull out when golden brown. Put on paper towels to drain.
Assemble sandwiches with lettuce, tomatoes, oysters, and remoulade sauce.