In a large mesh colander (like this one), mix the grated zucchini with the sea salt. Place a dish underneath the colander and set aside for 10 minutes. The salt will draw the liquid from the zucchini.Place the grated sweet potato and minced onion in a medium sized mixing bowl.Squeeze the excess liquid from the zucchini so it's very dry (I use my hands to do this – just grab a handful of it and squeeze the excess liquid right into the sink to discard the liquid and then blot with paper towels) and place it in the mixing bowl with the sweet potato and onion; mix well. Taste and add more salt and fresh ground black pepper if desired.Preheat a 12 inch skillet (this one is my favorite) over medium heat and add the oil. Once the pan is hot, add the hash browns. Use the back of a spatula to press the hash browns down into the pan. Allow the hash browns to cook for 3-6 minutes undisturbed. When the hash browns are slightly golden, flip them over in sections. Use the back of your spatula, again, to press them down into the pan. Cook another 3-6 minutes. Remove from heat and serve immediately.