Place the spiralized zoodles in a colander over the sink with a sprinkle of salt. Let sit for 15 minutes to release the moisture. After 15 minutes, squeeze the water out of the noodles with paper towels, then set aside to use in the recipe.
Meanwhile, add chicken breasts, ½ tablespoon of olive oil, and Cajun seasoning to a gallon-size Ziploc bag. Shake to coat in the seasoning and oil.
Heat the remaining tablespoon of olive oil in a large sauté pan over medium heat. Add chicken and cook until cooked through and chicken reaches 165 degrees F, about 4-7 minutes on each side depending on thickness. Set aside on a plate and let cool, then slice.
Add butter and garlic to the same hot pan. Stir until the butter is melted and the garlic is fragrant, about 1-2 minutes.
Stir in the half and half and cook for 2 minutes.
Meanwhile, mix the corn starch with the water, then add to the pan. (This will help thicken the sauce). Also stir in ½ cup of the Parmesan, pepper, and zucchini noodles. Cook, stirring often, until the zucchini noodles are heated through and slightly tender, about 3 minutes.
Add chicken back to the sauté pan and toss well. Taste and add salt if needed. Garnish with tomatoes, parsley, and the remaining ¼ cup of Parmesan. Enjoy!