Season the chicken breast evenly on both sides with the dried oregano, sea salt, and black pepper.
Heat the olive oil in a medium skillet over medium-high heat until shimmering.
Place the chicken in the skillet and sear for 6 to 8 minutes per side until the exterior is golden brown and the internal temperature reaches 165°F.
While the chicken cooks, place the chopped kale in a bowl and massage it with a small splash of the lemon juice for 1 minute until it softens and turns bright green.
In a serving bowl, layer the cooked quinoa and massaged kale as the base.
Top the base with the diced cucumber and halved cherry tomatoes.
Once the chicken is done, let it rest for 2 minutes before slicing it into thin strips.
Arrange the chicken over the vegetables, then garnish with crumbled feta cheese, fresh parsley, and the remaining lemon juice.