Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Combine the dry quinoa with the water in a small pot, bring to a boil, then simmer covered for 15 minutes until fluffy.
Dice the chicken breast, red bell pepper, and zucchini into bite-sized pieces.
Place the chicken and vegetables on the baking sheet, drizzle with olive oil, and season with sea salt, black pepper, and dried oregano.
Roast in the oven for 18-20 minutes until the chicken is cooked through and the vegetables are tender.
In a large bowl, whisk the lemon juice with any remaining pan juices, then fold in the cooked quinoa, roasted chicken, and vegetables.
Sprinkle with crumbled feta cheese before serving.