Bring a small pot of water to a boil and cook the orzo until al dente, then drain and set aside.
Season the chicken breast with half of the sea salt, black pepper, and dried oregano.
Heat a grill pan or outdoor grill to medium-high heat and cook the chicken for 6-7 minutes per side until the internal temperature reaches 165°F.
While the chicken cooks, heat the olive oil in a skillet over medium heat and sauté the minced garlic, diced zucchini, and diced red bell pepper until tender-crisp.
In a large bowl, combine the cooked orzo, sautéed vegetables, lemon juice, lemon zest, and the remaining salt, pepper, and oregano.
Slice the grilled chicken into strips and place them over the orzo mixture, then sprinkle with crumbled feta cheese before serving.