Preheat oven to 375 degrees.
Peel sweet potato and microwave on high for 3.5 - 4 minutes. (alternatively, you can boil a peeled sweet potato for 15 - 20 minutes instead). Let sweet potato cool for a few minutes so that you can safely handle it.
Using a medium to large grater, grate the sweet potato... adding it to a medium mixing bowl.
Then peel and grate the zucchini either over a thick paper towel or a tea towel. Once grated, squeeze out the excess "juice"/water from the zucchini.
Then add the remaining ingredients into the mixing bowl with the sweet potato: grated zucchini, parmesan cheese, sea salt, paprika, garlic powder, and flour. Mix well, even using your hands to press and squeeze and make sure everything is thoroughly combined.
Form the mixture into small cylinders with your fingers, making them about an inch and a half long. Set them on a lined baking sheet in rows so that they are not touching each other.
Bake for 20 minutes. Then, flip them over. Then bake for another 15 - 20 minutes, until lightly browned.
Combine the Greek yogurt and ketchup to make the dipping sauce.
Serve tots hot / immediately with the sauce.