Cut the zucchini into noodles using a vegetable spiralizer if not using precut zucchini.
In a large skillet over medium heat, melt butter. Add garlic and red pepper flakes and cook about 30 seconds. Add noodles for about 3 minutes. Do not over cook or the zucchini will be come mushy.
Toss cooked zucchini with parmesan and season with salt.