Preheat your grill to medium-high heat and lightly oil the grates.
In a small mixing bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, dried oregano, sea salt, and black pepper.
Place the salmon fillet and trimmed asparagus spears on a large plate or tray.
Brush the lemon-herb marinade generously over both the salmon and the asparagus, ensuring they are evenly coated.
Place the salmon on the grill, skin-side down, and cook for 5 minutes without moving it to ensure a good sear.
Add the asparagus to the grill and carefully flip the salmon fillet.
Grill both for an additional 3 to 4 minutes until the asparagus is tender-crisp and the salmon is opaque and flakes easily with a fork.
Remove from the grill and serve immediately with an extra squeeze of fresh lemon if desired.