Place a scoop of food-grade wood pellets into the wood pellet burner of your Ninja Woodfire grill. Remember to not use any wood pellets that are not food-grade safe.
Turn on the Ninja Woodfire grill to the ‘Smoke’ setting. Press the Woodfire Flavor Technology button. Next, set the heat to ‘Medium’ heat. Allow the Ninja Woodfire to Preheat. Be sure to not add food to the Ninja Woodfire until the display says ‘Add Food’, otherwise you risk your salmon falling apart due to sticking to a cold grill.
While the Ninja Woodfire is preheating, pat each salmon filet dry with a paper towel. Press the paper towel down gently to absorb some of the extra water.
Pour the oil into a large bowl. Dip each salmon filet into the oil on both sides. Set the salmon aside one by one.
Add a desired amount of salt and ground black peppercorn to each salmon filet.
Add the salmon to the preheated Ninja Woodfire grill, skin side down, and close the lid.
Allow the salmon to cook for 8 minutes on Medium Heat. Time may vary depending on the thickness and cut of your salmon filet.
Flip the salmon over and cook for 3-4 more minutes on the other side. Salmon is done when it is a pale pink, flaky, and has reached an internal temperature of at least 145 degrees fahrenheit.
Garnish with lemon slices (optional) and enjoy!