Place the whole wheat couscous in a heatproof mixing bowl. Add the kosher salt, black pepper, cayenne pepper, and 3 tablespoons of olive oil. Stir until the couscous is evenly coated. Smooth the surface and set aside.
Season the chicken breast on both sides with a pinch of kosher salt.
Heat 1 tablespoon of olive oil in a saucepan over high heat. Add the chicken and sear for 2 to 3 minutes.
Flip the chicken and add the diced red onion. Continue cooking for another 2 to 3 minutes, allowing the chicken to brown while the onion softens.
Transfer the chicken to a plate and let it cool for a few minutes. Cut it into approximately ½-inch cubes and return it to the saucepan.
Add the chicken broth, zucchini, green beans, red bell pepper, green onions, smoked paprika, and turmeric. Bring the mixture to a boil over high heat.
As soon as it boils, carefully pour the hot chicken and vegetable mixture over the prepared couscous. Do not stir.
Immediately cover the bowl tightly with aluminum foil and let it stand for 5 minutes.
Remove the foil and add the chopped parsley. Fluff and stir everything together, then taste and adjust the seasoning if needed.
Spoon the Chicken Couscous into serving bowls. Finish with crumbled feta, chili flakes, fresh parsley, and an optional drizzle of olive oil.