Preheat your oven to 400°F and line a baking sheet with parchment paper for easy cleanup.
Slice the zucchini into half-moons and toss them on the baking sheet with half of the olive oil, a pinch of sea salt, and black pepper.
Roast the zucchini in the oven for 15 to 18 minutes until they are tender and show light golden edges.
While the vegetables roast, season the chicken breast evenly on both sides with the dried oregano and the remaining salt and pepper.
Heat the remaining olive oil in a medium skillet over medium-high heat until shimmering.
Place the chicken in the skillet and sear for 6 to 7 minutes per side, or until the exterior is golden brown and the internal temperature reaches 165°F.
Reduce the heat to low, add the minced garlic to the pan, and sauté for 1 minute until fragrant, being careful not to burn it.
Plate the seared chicken over the warm cooked quinoa, serve the roasted zucchini alongside, and finish the entire dish with a fresh squeeze of lemon juice.