Many times zucchini noodles get watery when they are cooked too long and the zucchini releases too much water. If this happens, drain off the excess water or dry the noodles with a paper towel to remove some noodles.
Another trick is to salt the zucchini noodles. Place the spiralized noodles in a colander. Sprinkle them with kosher salt and toss. Let sit in the colander for 15-30 minutes. Then rinse the noodles and dry well. This removes some of the moisture from the zucchini and will result in a better texture.