Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Toss the cubed sweet potatoes with half of the avocado oil and a pinch of salt, then spread them in a single layer on the baking sheet.
Roast the sweet potatoes for 15 minutes.
Add the trimmed asparagus to the baking sheet, drizzle with a tiny bit of water or additional oil spray if needed, and roast for another 10 minutes until the vegetables are tender.
While the vegetables roast, season the salmon fillet with garlic powder, salt, and black pepper.
Heat the remaining avocado oil in a cast-iron skillet over medium-high heat.
Place the salmon in the skillet skin-side down and sear for 4-5 minutes until the skin is crispy and golden.
Carefully flip the salmon and cook for an additional 2-3 minutes until the fish is just opaque in the center.
Plate the seared salmon alongside the roasted sweet potatoes and asparagus.
Finish the dish with a bright squeeze of fresh lemon juice and a sprinkle of flaky sea salt.