Pat the chicken dry with paper towels. A wet chicken will cause the oil to splatter while the chicken is sautéing. Mix the cinnamon, salt and pepper in a small bowl. Rub the chicken pieces on all sides with the seasoning.
Heat the olive oil in a large, nonreactive, deep skillet over high heat. A 12-inch skillet with sides about 2 1/2 to 3 inches high will allow you to brown all the chicken at once. If you don't have a skillet large enough, brown them in two batches using 1/2 the oil for each batch. What's important is that the chicken isn't overcrowded, which would cause them to steam rather than brown.
Add the chicken to the oil and brown for about 4 to 5 minutes on each side. Turn the pieces using a metal spatula, as they have a tendency to stick to the pan. Remove the pieces when they are well browned on all sides.
Mince three of the garlic cloves. Lower the heat to medium-high, and add the onions and minced garlic. Cook for about 3 minutes, stirring constantly, until the onions have softened and are a rich golden brown. Add about 1/2 cup of the water and scrape the bottom of the pan with a spatula or spoon to deglaze the pan, loosening any particles stuck on the bottom.
When the water has evaporated, add the remaining 1 1/2 cups of water, tomato paste, Italian seasoning and remaining 2 garlic cloves, minced.
Return the chicken to the pan. The liquid should cover about 3/4 of the chicken pieces. Cover the pot and simmer over medium-high heat for about 30 to 40 minutes, or until the chicken is tender and thoroughly cooked. If the sauce becomes too thick, it can be thinned with a little more water. Season the finished sauce with kosher salt and pepper to taste. Serve over orzo, cooked according to package directions, and sprinkle Parmesan cheese on top.