01 - Preheat the oven to 400°F. Line a large baking sheet with parchment paper or foil for easy cleanup.
02 - Arrange the asparagus in a single layer on one half of the sheet pan. Drizzle with 1 tablespoon olive oil, season with 1/2 teaspoon salt and 1/4 teaspoon pepper, and toss to coat evenly.
03 - In a small bowl, whisk together remaining 2 tablespoons olive oil, lemon zest, lemon juice (reserve a few slices for garnish), garlic, parsley, dill, 1/2 teaspoon salt, and 1/4 teaspoon pepper.
04 - Place the salmon fillets skin-side down on the other half of the sheet pan. Brush the lemon herb mixture generously over the salmon, using any remaining mixture to drizzle over the asparagus.
05 - Top each salmon fillet with a lemon slice. Roast in the preheated oven for 15-18 minutes, or until the salmon is opaque and flakes easily with a fork, and the asparagus is tender-crisp.
06 - Serve immediately, garnished with extra herbs and lemon wedges if desired.