Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Trim the tough, woody ends off the asparagus spears and place them on one side of the prepared baking sheet.
Drizzle the asparagus with the extra virgin olive oil and sprinkle with half of the sea salt and black pepper, tossing to coat evenly.
Place the salmon fillet on the other side of the baking sheet.
Mince the garlic clove and finely chop the fresh parsley.
In a small bowl, mix the minced garlic, parsley, and dried oregano, then rub the mixture over the top of the salmon fillet.
Sprinkle the remaining sea salt and black pepper over the salmon.
Slice the half lemon into thin rounds and arrange them over the salmon and asparagus.
Roast in the center of the oven for 12-15 minutes, or until the salmon flakes easily with a fork and the asparagus is crisp-tender.
Serve immediately, drizzling any remaining juices from the pan over the fish.