Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Pat the chicken breast dry with a paper towel, then season both sides evenly with sea salt, black pepper, and dried oregano.
Place the chicken on one side of the prepared sheet pan and roast for 12 minutes.
While the chicken starts roasting, trim the woody ends off the asparagus and mince the garlic cloves.
In a small bowl, whisk together the extra virgin olive oil and minced garlic.
Remove the pan from the oven, place the asparagus on the other side, and drizzle the garlic-oil mixture over the spears, tossing gently to coat.
Slice the half lemon into thin rounds and layer them over the chicken and asparagus.
Return the pan to the oven and roast for another 10-12 minutes until the chicken reaches an internal temperature of 165°F and the asparagus is tender.
Serve the roasted chicken and asparagus over the warm cooked quinoa, drizzling any remaining pan juices over the top.