Season the chicken breast evenly on both sides with sea salt, black pepper, and dried oregano.
Heat a non-stick skillet over medium-high heat with half of the olive oil.
Place the chicken in the skillet and sear for 6-7 minutes per side until the internal temperature reaches 165°F and the exterior is golden brown.
While the chicken cooks, dice the cucumber, halve the cherry tomatoes, and finely mince the garlic and fresh parsley.
In a small bowl, whisk together the remaining olive oil, lemon juice, minced garlic, and parsley to create the dressing.
Once the chicken is cooked, let it rest for 5 minutes before slicing it into thin strips or bite-sized cubes.
In a large mixing bowl, combine the cooked quinoa, cucumber, and tomatoes.
Add the sliced chicken to the bowl and drizzle the lemon-herb dressing over the top.
Toss everything together until well combined and serve immediately.