Heat the vegetable oil in a large saucepan over high heat. Cook the Idaho and sweet potatoes until they begin to get some color, approximately 10 minutes. Season with kosher salt while cooking. Turn the heat down to medium and add the garlic, green onions, Spanish onions, paprika and cayenne and cook for another 10 minutes. Add the brisket and some of the braising liquid, scraping the bottom of the pan with a wooden spoon. Add more braising liquid if the pan seems dry and bring to a simmer to bring all of the ingredients together. Season to taste. Serve with a fried egg on top and a side of Texas toast!