Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a small saucepan, combine the quinoa and water; bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes until the water is absorbed.
Mince the garlic clove and set aside.
Pat the chicken breast dry and place it on the prepared baking sheet.
Rub the chicken with half of the olive oil, the minced garlic, dried oregano, sea salt, and black pepper.
Roast the chicken in the oven for 10 minutes.
Trim the woody ends off the asparagus and toss the spears with the remaining olive oil.
Add the asparagus to the baking sheet alongside the chicken and roast for an additional 10 to 12 minutes, or until the chicken reaches an internal temperature of 165°F.
Fluff the cooked quinoa with a fork and place it on a plate.
Slice the chicken and serve it over the quinoa with the roasted asparagus, drizzling everything with fresh lemon juice before eating.