Preheat oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Toss the cubed sweet potatoes with half of the olive oil, sea salt, and black pepper, then spread them on the baking sheet.
Roast the sweet potatoes for 10 minutes before adding the other components.
While potatoes roast, whisk together the Dijon mustard, almond meal, parsley, and dill in a small bowl to create the herb paste.
Pat the salmon dry and spread the herb paste evenly over the top of the fillet.
Move the sweet potatoes to one side of the tray, then add the salmon and the asparagus (tossed in remaining oil) to the other side.
Bake for an additional 12-15 minutes until the salmon is flaky and the sweet potatoes are tender and golden.
Serve immediately with a fresh lemon wedge squeezed over the fish.