Put the chicken in a large bowl. Add 1 tablespoon olive oil, 1 tablespoon of parsley, and the lemon juice and zest. Season with salt and a generous amount of freshly ground black pepper. Put the chicken in the refrigerator to marinate for 1 hour. Remove the chicken from the refrigerator.

While the chicken is marinating, in a medium pot, bring salted water to a boil. Add the peas and cook for 4 minutes. Remove from the heat, drain, and put them in a small bowl filled with ice water. Drain and set aside.

Heat 1 tablespoon olive oil in a large skillet over medium heat. Add the chicken and cook for 8 minutes. Turn the chicken over and cook for approximately 8 minutes longer or until the chicken is cooked through. Transfer the chicken to a warm plate and set aside.

Put the couscous in a small pot. Pour the boiling water over the couscous and cover. Let sit for 6-7 minutes.

Heat the remaining olive oil in a large pan over medium-low heat. Add the onion, garlic, peas, 1 tablespoon parsley, thyme, and season with salt and pepper. Cook for 5 minutes, gently stirring. Reduce the heat to low. Add the couscous to the pan, stir to combine, and cook for an additional minute.