Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
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.
Remove the tray from the oven, add the asparagus spears, drizzle with a touch of water or a tiny bit more oil if needed, and season with salt and pepper.
Return the vegetables to the oven and roast for another 10-12 minutes until the potatoes are tender and the asparagus is crisp-tender.
While the vegetables roast, pat the salmon fillet dry with a paper towel and season both sides with salt, pepper, and garlic powder.
Heat the remaining avocado oil in a stainless steel or cast-iron skillet over medium-high heat.
Place the salmon in the hot pan, skin-side down, and sear for 4-5 minutes until the skin is crispy and releases easily from the pan.
Flip the salmon and cook for an additional 2-3 minutes until your desired level of doneness is reached.
Plate the seared salmon alongside the roasted sweet potatoes and asparagus, finishing the dish with a fresh squeeze of lemon juice.