Put the salt and water in a saucepan over medium heat. Stir until the salt dissolves in the water. Do not boil the solution.
Put the salmon in a small glass baking dish. Cover it completely with the saltwater brine. Let the salmon rest in the brine in the refrigerator for 24 hours.
After 24 hours, remove the salmon from the brine, rinse it with cold water, and pat it dry with paper towels.
Mix the dill, black pepper, lemon zest, and mustard powder together. Rub this mixture all over the skinless side of the salmon.
Let the seasoned salmon rest in a single layer in the refrigerator for 2-4 hours. This step is important to form the pellicle which will help the smoke flavor to adhere to the fish.
Set up your full-size Nordic Ware smoker with 2-3 T of shredded wood chips that are meant for smoking food. I used the hickory chips that came with the smoker.
Put the drip pan and smoking tray in the smoker. Put the salmon skin-side down in a single layer on the smoking tray.
Put the lid on the smoker. Ensure the thermometer is attached properly and the lid vent is closed. Turn your stovetop vent fan on.
Put the smoker on a stovetop burner and turn the heat to medium-low. Allow the smoker's thermometer to come to 190°F (88°C).
Once the temperature comes to 190°F (88°C), turn the stovetop to low, and set a timer to smoke the salmon for 20-30 minutes. I chose to smoke the salmon for 25 minutes. Make sure that the smoker stays in the 190°F-210°F (88°C-99°C) range for the entire smoking period. You may need to adjust the stovetop's heat or open the vent on the lid. Keep a close eye on things!
If the heat on the smoker is rising too rapidly, you can always quickly lift the lid and peek at your salmon. This is an easy way to help bring the temperature back down.
After the timed smoking period, turn off the stovetop and remove the salmon from the smoker. Extinguish the spent wood chips by soaking them in water.
Refrigerate the salmon and serve it chilled. So delicious!