Prepare the fusilli according to the package directions in a 6-quart saucepot. Add the spinach during the last minute of the cooking time. Drain the fusilli mixture well in a colander, reserving 1 cup cooking liquid.
Heat the oil in a 12-inch skillet over medium-high heat. Add the chicken and cook until well browned, stirring occasionally.
Add the garlic to the skillet and cook and stir for 1 minute. Stir in the tomatoes, soup, 1/2 cup cooking liquid and red pepper and heat to a boil. Reduce the heat to low. Cook until the chicken is cooked through, stirring occasionally. Stir in the fusilli mixture and cook until the mixture is hot and bubbling. Stir in the remaining cooking liquid as needed until desired consistency. Sprinkle with the cheese.
Time-Saving: You may substitute 1 package (about 9 ounces) refrigerated fully-cooked chicken strips for the chicken breast halves. Stir in the chicken with the soup.