Bring a large pot of water plus 1 tablespoon of salt to a boil. Add the potatoes, bring back to a boil and then lower the temperature to simmering. Simmer for 15 minutes. Drain in a colander.

Heat one side of a gas grill to Medium or 300 degrees. Coat both sides of the onion slices with vegetable oil or cooking spray. When the grill is at temperature, clean the grill with a wire brush. Using a set of long tongs, bunch up one of the pieces of bacon (so it is compact) and rub it on the prepared grill surface. Place the onion slices on the grill.

Allow the slices to sit on the grill until the onion begins to soften, and develop grill marks. Gently flip the slices and cook on the other side. When done the onions will become soft and more pliable as well as a more translucent; about 10 minutes. Remove and set aside.

Double a piece of foil to make a 10-inch by 7-inch (approximately) foil tray. Bend the edges up slightly. Place the foil on the hot side of the grill toward the back so as to not be in the way. Add a handful of apple wood and close the grill lid.

As the wood is heating to start to smoke, add the drained potatoes to a grill basket or form a basket of double layer foil poking holes in the foil to allow the smoke to penetrate the potatoes. Once the wood has begun to smoke, add the potatoes to the unheated said of the grill (opposite side to the wood) and close the grill.

After 10 minutes, place the hard boiled eggs and the two strips of bacon on the unheated side of the grill and close the lids. The eggs and the potatoes will take on a yellow hue as they become penetrated by the smoke. As the bacon cooks turn it once during the cooking (it will cook through but not become crisp except the edges). Remove the potatoes, eggs and bacon after 20 minutes. Total smoking time for the potatoes: 30 minutes. Total smoking time for the eggs and bacon: 20 minutes. Turn off the grill and allow the foil smoking tray to cool before removing.

As the smoked items cool slightly, combine the mayonnaise, sour cream, both mustards in a bowl and stir to combine.

Chop each the grilled onion, smoked eggs and bacon. Add them to a large mixing bowl along with the potatoes and celery; stir to combine. Spoon the sauce into the bowl and sprinkle with 2 teaspoons Kosher Salt and 1 teaspoon Black Pepper. Stir to combine all ingredients. Cover and place in the refrigerator for a few hours for the flavors to blend (the flavor does change over that chilling time; the light taste of the smoke becomes more notable). Serve chilled or at room temperature. Note: mayonnaise-based salads should not be left in the heat or set out at room temperature for more than a few hours due to risk of food poisoning.