Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Trim the tough, woody ends off the asparagus spears and place them on the prepared baking sheet.
Drizzle the asparagus with the extra virgin olive oil and season with half of the sea salt and black pepper, tossing to coat evenly.
Roast the asparagus in the oven for 12 to 15 minutes until they are tender and slightly charred at the tips.
While the asparagus roasts, pat the chicken thighs dry with a paper towel and season both sides with the dried oregano and the remaining salt and pepper.
Heat the avocado oil in a large cast-iron or stainless steel skillet over medium-high heat until the oil is shimmering.
Carefully place the chicken thighs in the skillet and sear for 6 to 8 minutes per side, without moving them, until they are golden brown and reach an internal temperature of 165°F.
In the final minute of searing, add the minced garlic and lemon zest to the pan, stirring quickly to infuse the oil and coat the chicken without burning the garlic.
Remove the skillet from the heat and drizzle the fresh lemon juice over the chicken thighs.
Serve the pan-seared chicken immediately alongside the roasted asparagus spears.