I am an outsider and all regional recipes are very different but I am pretty sure mayo and mustard are the basis for a remoulade
Well, you made me go look up remoulade sauce. Here’s a recipe for a sauce for crab cakes...
http://www.food.com/recipe/mini-crab-cakes-with-remoulade-sauce-45504
Doesn’t sound too bad! Kind of a spicy tartar sauce.