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 snap off the woody bottom ends, then spread the spears out on one half of the prepared baking sheet.
Pat the salmon fillet dry with a paper towel to ensure a good roast and place it on the other half of the baking sheet.
In a small glass bowl, whisk together the olive oil, lemon juice, orange zest, minced garlic, and dried oregano until well combined.
Drizzle the citrus-herb mixture evenly over both the salmon fillet and the asparagus spears.
Sprinkle the sea salt and black pepper over everything, tossing the asparagus slightly to coat.
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 and bright green.
Serve immediately, optionally garnished with extra fresh herbs or a slice of lemon.