Season the chicken breast evenly on both sides with sea salt, black pepper, and dried oregano.
Heat half of the olive oil in a medium skillet over medium-high heat.
Add the chicken to the skillet and sear for 5-7 minutes per side until the internal temperature reaches 165°F and the outside is golden brown.
While the chicken cooks, mince the garlic and finely chop the parsley, cucumber, and cherry tomatoes.
In a small jar or bowl, whisk together the remaining olive oil, lemon juice, and minced garlic to create the dressing.
In a large mixing bowl, combine the cooked quinoa with the cucumber, cherry tomatoes, and parsley.
Remove the chicken from the pan and let it rest for 3 minutes before slicing into thin strips.
Pour the lemon dressing over the quinoa mixture and toss thoroughly to combine.
Transfer the quinoa salad to a plate and top with the sliced lemon-herb chicken.