Preheat the oven to 425. Line a baking sheet with parchment paper and set aside.
Make the BBQ Rub by mixing together in a small bowl, the smoked paprika, chili powder, garlic powder, onion powder, and pepper. Set aside.
Add the sweet potatoes to the parchment paper-lined baking sheet. Drizzle with avocado oil, 2 teaspoons of the barbecue rub, and salt. Toss to combine.
Transfer to the oven and bake on the middle rack for 10 minutes.
Carefully remove the baking sheet from the oven and move the sweet potatoes to one side of the sheet.
Add the salmon filets to the sheet pan, skin side down. Drizzle the avocado oil over the salmon fillets, massaging it into the flesh. Season with salt, and coat liberally with the remaining BBQ spice rub.
Transfer the sheet pan back to the oven and bake for 10 minutes.
Remove from the oven once more, then baste BBQ sauce onto each salmon fillet. Transfer the sheet back to the oven and cook for 5 more minutes, until the fish easily flakes when pressed with a fork and the sweet potatoes are charred in places. Allow to cool slightly before assembling the bowls.