Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Wash the asparagus and trim away the tough, woody ends, then spread the spears out on one side of the prepared baking sheet.
Place the salmon fillet on the other side of the baking sheet, ensuring there is space between the fish and the vegetables.
In a small glass bowl, whisk together the olive oil, fresh lemon juice, minced garlic, and dried oregano until well combined.
Drizzle the lemon-herb mixture evenly over both the salmon and the asparagus spears.
Season everything with the sea salt and freshly cracked black pepper.
Bake for 12 to 15 minutes, or until the salmon is opaque and flakes easily with a fork and the asparagus is tender-crisp.
Serve immediately, optionally garnished with fresh lemon slices for extra brightness.