Preheat your oven to 400°F and line a rimmed baking sheet with parchment paper.
Rinse the quinoa in a fine-mesh sieve, then combine it with 0.5 cup of water in a small saucepan; bring to a boil, then reduce heat and simmer covered for 15 minutes.
In a small bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, dried oregano, garlic powder, sea salt, and black pepper.
Place the chicken breast and the trimmed asparagus spears on the prepared baking sheet.
Brush half of the lemon-herb mixture over the chicken breast and drizzle the remaining half over the asparagus, tossing to coat evenly.
Roast in the oven for 18 to 22 minutes, or until the chicken is cooked through and the asparagus is tender and slightly browned.
Remove from the oven, let the chicken rest for 5 minutes, then slice and serve over the fluffed quinoa.