Preheat your oven to 400°F (200°C) and line a small baking sheet with parchment paper.
Trim the woody ends off the asparagus and place them on the baking sheet, tossing with half of the olive oil and a small pinch of the salt and pepper.
In a small bowl, combine the smoked paprika, garlic powder, onion powder, oregano, thyme, cayenne, and the remaining sea salt and black pepper to create the Cajun rub.
Pat the salmon fillet dry with a paper towel and coat the top surface generously with the spice blend, pressing it in firmly to ensure it sticks.
Place the asparagus in the oven to roast for 12-15 minutes until tender-crisp and slightly charred.
While the asparagus roasts, heat the remaining olive oil in a non-stick skillet over medium-high heat.
Place the salmon spice-side down in the hot skillet and sear for 3-4 minutes without moving it, until a dark, golden crust forms.
Flip the salmon carefully and cook for another 3-4 minutes until the internal temperature reaches 145°F and the fish flakes easily with a fork.
Plate the salmon alongside the roasted asparagus and serve immediately with fresh lemon wedges for squeezing over the fish.