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 sea 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, tossing with a tiny bit more oil if needed, and roast everything for another 10 minutes until the vegetables are tender.
While the vegetables roast, pat the salmon fillet completely dry with a paper towel and season with salt and pepper.
Heat the remaining avocado oil in a cast-iron or stainless steel skillet over medium-high heat until shimmering.
Place the salmon skin-side down in the pan and press gently with a spatula for 10 seconds to ensure even contact.
Sear the salmon for 4-5 minutes until the skin is perfectly crisp and the flesh is cooked halfway up the side.
Carefully flip the fillet and cook for another 2-3 minutes until it reaches your desired level of doneness.
Plate the salmon alongside the roasted vegetables and finish with a fresh squeeze of lemon juice and a sprinkle of flaky sea salt.