Arrange the top oven rack close to the top of the oven near the broiler and turn on the broiler. Spread the olive oil (1 tablespoon) on the center of a rimmed baking sheet (across enough surface area for the size of the salmon).
Place the salmon skin side up on a rimmed baking sheet on top of the oil. and season the skin side with 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper. Flip over so the skin side is down. Season the top with the remaining 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper.
Brush the top of the salmon with about a third, or 2 tablespoons, of the bbq sauce (don't bother getting a measuring spoon dirty- just approximate this, and lay it on thick). Broil on the top oven rack for about 3 minutes, and brush the top with more bbq sauce. Broil for 3 more minutes, brush with bbq sauce, and again after 3-4 more minutes (for a total of 10 minutes). Continue broiling if necessary for a few more minutes until salmon is fully cooked (you can check it by seeing if it flakes apart easily with a fork or the internal temperature is 145 degrees F).
Serve with more bbq sauce if desired.
BBQ sauce with sugar will result in a thick, sticky, caramelized layer. If you use a whole30 or no-sugar sauce, keep in mind the result may be different and not thicken or brown quite as much. I used homemade bbq sauce. For a low carb version, use a low carb or no sugar BBQ sauce.
For crispy skin, sear the salmon skin-side down in a very hot oiled skillet for 1-2 minutes before proceeding with the recipe. If you use an oven safe skillet, you can just proceed to broil and keep the salmon right in the same skillet for less clean-up and super crispy skin.
For a gluten-free version, be sure to use a gluten free BBQ sauce.
To get the thickest layer of BBQ sauce, "dollop" the sauce on rather than "brush," otherwise you might brush off some of the existing layers of sauce.