Prepare the Chicken: In a medium bowl, combine the chicken chunks, half of the minced garlic, rosemary, oregano, lemon zest, red pepper flakes (if using), 2 tablespoons of olive oil, sea salt, and black pepper. Toss thoroughly until the chicken is evenly coated.
Sear the Chicken: Heat the remaining 2 tablespoons of olive oil in a large, 12-inch oven-safe skillet over medium-high heat. Once shimmering, add the chicken pieces in a single layer. Sear for 3-4 minutes per side, until deeply golden brown. Transfer the seared chicken to a clean plate. The chicken will not be fully cooked.
Sauté the Vegetables: Reduce the heat to medium. Add the sliced red onion to the skillet and cook for 4-5 minutes, until softened. Add the finely diced zucchini and the remaining minced garlic, and cook for another 2 minutes until fragrant.
Blister and Toast: Add the cherry tomatoes and cook, stirring occasionally, for about 5 minutes, until they begin to blister and burst. Add the whole-wheat orzo and stir constantly for 1 minute to lightly toast the grains.
Simmer the Orzo: Pour in the low-sodium chicken broth, scraping up any browned bits from the bottom of the pan. Stir in the halved Kalamata olives and bring the mixture to a simmer.
Cook Together: Nestle the seared chicken pieces and any accumulated juices back into the orzo mixture. Reduce the heat to low, cover the skillet, and simmer for 12-15 minutes, or until the orzo is tender, most of the liquid is absorbed, and the chicken is cooked through (165∘F or 74∘C).
Broil and Rest: Position an oven rack about 6 inches from the heat source and preheat the broiler. Uncover the skillet and broil for 2-3 minutes, watching carefully, until the tops of the chicken are lightly browned. Remove from the oven and let rest for 5 minutes.
Finish and Serve: Stir in the fresh lemon juice. Garnish generously with fresh parsley and oregano before serving.