Heat oven to 450°. Place salmon and asparagus on separate baking pans. Drizzle 1 tbsp of the olive oil over asparagus; season salmon and asparagus with 1/2 tsp of the salt and 1/4 tsp of the pepper. Roast at 450° for 12 to 14 minutes, until salmon flakes and asparagus is tender. Cut asparagus into 1-inch pieces.
Meanwhile, whisk sour cream, remaining 1 tbsp olive oil, the lemon juice, garlic, mustard, Worcestershire, anchovy paste (if using), remaining 1/4 tsp each salt and pepper and 3 tbsp of the Parmesan. Set aside.
In a large bowl, toss romaine, onion, tomatoes and asparagus. Add half the dressing and remaining 2 tbsp Parmesan; toss to coat.
Serve salad with salmon and remaining dressing on the side.