In the 4-quart pot, bring the water to a boil and cook the orzo according to the package directions, just until al dente. Do not overcook or it will be mushy. Drain, reserving ¼ cup of the liquid, and keep warm.
While the orzo cooks, sauté the chicken pieces dry in the skillet until they are cooked through and lightly browned. Transfer to a plate and cover to keep warm.
Add the tomatoes, slow-roasted tomatoes (or tomato paste), salt, crushed pepper, and reserved cooking liquid to the skillet. Cook over over medium-high heat for 2 minutes. Stir in the chicken, orzo, and the basil leaves, leaving in the skillet just until the basil wilts, about 1 minute. Serve with a sprinkle of Parmesan.