Place potatoes and eggs in a large pot and add enough water to cover them by at least 1 inch. Add about 1 tablespoon of salt.Bring to a boil. Let boil for 8 minutes and then remove the eggs and place them in a bowl of ice water.Continue to boil the potatoes until fork tender. (Should take about 20 to 25 minutes total depending on size of your potato pieces.)
When eggs have cooled, peel them and separate the yolks from the egg whites.
Place mayonnaise, mustard, and egg yolks in a medium bowl. Mash the yolks into the mayonnaise and stir to mix.
When potatoes are cooked, drain them and transfer to a large bowl. Use a potato masher to break the potatoes up and mash them a little.
Add mayonnaise mixture to potatoes and mix in.Stir in Cajun seasoning, pickle relish, celery, and green onions.
Check for saesoning and season to taste with salt and pepper. You probably won't need much salt, but I recommend adding at least 1/2 teaspoon of black pepper.
Sprinkle with paprika and parlsey and refrigerate at least 30 minutes before serving.