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 bottom ends, then place the spears on one side of the prepared baking sheet.
Pat the salmon fillet dry with a paper towel and place it on the other side of the baking sheet.
In a small ramekin, whisk together the extra virgin olive oil, minced garlic, dried oregano, sea salt, and black pepper.
Drizzle the herb oil over both the salmon and the asparagus, using your hands or a brush to ensure the asparagus is evenly coated.
Thinly slice half of the lemon into rounds and lay them across the top of the salmon fillet.
Roast in the center of the oven for 12 to 15 minutes, or until the salmon flakes easily with a fork and the asparagus is tender-crisp.
Remove from the oven and squeeze the remaining lemon juice over everything before serving immediately.