Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Trim the tough, woody ends off the asparagus and spread the spears in a single layer on one side of the baking sheet.
Drizzle the asparagus with olive oil and sprinkle with a pinch 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.
In a small mixing bowl, combine the Dijon mustard, almond flour, dried parsley, garlic powder, and the remaining salt and pepper to create a thick paste.
Spread the herb-mustard mixture evenly over the top of the salmon fillet, pressing down slightly so the crust adheres.
Place the baking sheet in the oven and roast for 12 to 15 minutes, or until the salmon flakes easily with a fork and the crust is golden.
Remove from the oven and squeeze the fresh lemon juice over both the salmon and the roasted asparagus before serving.