Preheat your oven to 400°F and line a baking sheet with parchment paper for easy cleanup.
Toss the cubed sweet potatoes with half of the avocado oil, salt, and pepper, then spread them in a single layer on the baking sheet.
Roast the sweet potatoes for 15 minutes, then move them to one side of the tray and add the asparagus spears.
Drizzle the asparagus with a tiny bit of water or the remaining oil and roast everything for another 10 minutes until the vegetables are tender.
While the vegetables finish roasting, pat the salmon fillet completely dry with a paper towel and season both sides with salt and pepper.
Heat a non-stick skillet over medium-high heat with the remaining avocado oil.
Place the salmon in the pan skin-side down and sear for 4 to 5 minutes until the skin is golden and crisp.
Flip the fillet carefully and cook for an additional 2 to 3 minutes until the salmon is just cooked through.
Plate the seared salmon alongside the roasted sweet potatoes and asparagus, finishing the dish with a bright squeeze of fresh lemon juice.