Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Trim the tough, woody ends off the asparagus spears and place the spears 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 half of the black pepper, tossing to coat well.
In a small mixing bowl, whisk together the Dijon mustard, dried parsley, dried dill, garlic powder, and lemon juice until a thick paste forms.
Place the salmon fillet on the other side of the baking sheet and spread the herb-mustard mixture evenly over the top of the fish.
Season the salmon with the remaining sea salt and black pepper.
Bake for 12 to 15 minutes, depending on the thickness of the fillet, until the salmon is opaque and flakes easily with a fork and the asparagus is tender and lightly browned.