Place eggs in a sauce pan so that they are crowded with little room to move around. Cover with water and add 1 tablespoon of salt. Bring to a full, rolling boil (about 10 minutes on high), then immediately cover the pot and turn off heat, but leave the pot on the stove eye. Allow to sit covered for 15 minutes. Carefully drain the pot and place under the faucet tap, letting the eggs rinse under a steady stream of water, emptying and refilling the pot with cool water several times until the water is no longer hot. Let the eggs rest for 10 minutes in the cool water. Peel the eggs and split in half lengthwise, removing the yolks and setting aside the whites. Using a fork or pastry blender, mash the yolks well. To the yolks, add mustard, pickle relish, salt, pepper and Cajun seasoning and stir together, adding only enough of the mayonnaise for desired consistency. Taste and adjust seasonings as needed. Pipe the yolk mixture into the egg whites using either a pastry bag and tips or place into a plastic storage bag and snip off the corner. Piping not only looks nicer, but it also makes more efficient use of the yolk filling. Serve immediately or refrigerate filled eggs in a covered bowl that leaves room so the stuffing is not disturbed.