Season the chicken breast evenly with half of the sea salt, black pepper, and dried oregano.
Heat a non-stick skillet over medium-high heat with a small drizzle of the olive oil and sear the chicken for 6-7 minutes per side until the internal temperature reaches 165 degrees Fahrenheit.
While the chicken rests, whisk together the remaining olive oil, lemon juice, salt, pepper, and oregano in a small bowl to create the vinaigrette.
In a large mixing bowl, combine the cooked quinoa, diced cucumber, halved cherry tomatoes, and finely chopped red onion.
Slice the rested chicken into bite-sized strips or cubes and add it to the bowl with the quinoa and vegetables.
Drizzle the lemon-herb dressing over the salad, sprinkle with freshly chopped parsley, and toss gently to combine before serving.