Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Snap off the woody ends of the asparagus spears and place them on one side of the prepared baking sheet.
Drizzle the asparagus with olive oil and sprinkle with a portion of the sea salt and black pepper, tossing to coat.
Pat the salmon fillet dry with a paper towel and place it on the other side of the baking sheet.
Spread the Dijon mustard in a thin, even layer over the top of the salmon fillet.
In a small bowl, combine the panko breadcrumbs, dried parsley, garlic powder, and the remaining salt and pepper.
Press the breadcrumb mixture firmly onto the mustard-coated salmon to create an even crust.
Roast in the oven for 12 to 15 minutes, or until the salmon is opaque and the crust is beautifully golden brown.
Remove from the oven and finish with a bright squeeze of fresh lemon juice over the salmon and asparagus before serving.