Marinate the chicken. In a large bowl or zip-top bag, whisk 2 tablespoons of the olive oil with the lemon juice, garlic, oregano, basil, salt, pepper, and paprika. Add the chicken, turn to coat, and refrigerate for 30 minutes (no more than 2 hours — the acid will start to make the texture mushy past that).
Prep the quinoa and vegetables. While the chicken marinates, cook the quinoa according to package directions (usually 15 minutes). Toss the broccoli with the remaining 1 tablespoon of olive oil and a pinch of salt.
Cook the chicken. Heat a grill pan or skillet over medium-high heat. Remove the chicken from the marinade (let excess drip off) and cook 6–7 minutes per side, until the thickest part reads 165°F on an instant-read thermometer — that's the USDA-recommended safe internal temperature for chicken. (My skillet has hot spots, so I rotate the breasts once for even browning.)
Rest — don't skip this. Transfer the chicken to a cutting board and rest for 5 minutes. This lets the juices redistribute instead of running all over the board. Slice against the grain.
Char the broccoli. In the same hot pan, sear the broccoli 4–5 minutes until bright green with charred edges. A little char adds smoky flavor for zero extra calories.
Assemble the bowls. Divide the quinoa among 4 bowls. Top with sliced chicken, charred broccoli, cherry tomatoes, and cucumber. Sprinkle with feta and parsley. Squeeze extra lemon over everything and serve.