Season the chicken breast with 0.125 tsp sea salt, 0.125 tsp black pepper, and 0.5 tsp dried oregano.
Heat a skillet over medium heat and cook the chicken for 6-7 minutes per side until golden and cooked through.
In a small bowl, whisk the extra virgin olive oil, lemon juice, minced garlic, and the remaining salt, pepper, and oregano to create a zesty dressing.
Dice the cucumber, halve the cherry tomatoes, and finely dice the red onion.
In a large bowl, combine the cooked quinoa, baby spinach, and prepared vegetables.
Slice the chicken, add it to the bowl, drizzle with the dressing, and toss everything together until well combined.