Preheat your oven to 425°F (220°C) and line a rimmed baking sheet with parchment paper.
Pat the chicken thighs completely dry with paper towels; this is the secret to achieving perfectly crispy skin.
Mince the garlic, rosemary, and thyme, then combine them in a small bowl with half of the olive oil, sea salt, and black pepper.
Carefully loosen the skin of the chicken with your fingers and rub half of the herb mixture directly onto the meat, then rub the remaining mixture over the top of the skin.
Place the chicken thighs on the prepared baking sheet and roast for 15 minutes.
While the chicken starts roasting, trim the woody ends off the asparagus and toss the spears with the remaining olive oil.
Remove the baking sheet from the oven, arrange the asparagus and lemon slices around the chicken, and return to the oven for another 10-15 minutes.
Roast until the chicken reaches an internal temperature of 165°F and the skin is golden brown and crackling.
Let the chicken rest for 5 minutes before serving to keep the meat juicy.