Preparation: (Make the polenta pieces at least 1 hour in advance.) Make the Polenta Pieces: Pour 1-3/4 cups water into a medium-sized saucepan, add the salt, and bring to a boil. Meanwhile, place the polenta in a bowl with the cold water, and stir until it is completely moistened. Turn heat under the boiling water down to a simmer, and spoon in the wet polenta. Stir with a wooden spoon, and cook over medium-low heat for about 5 to 8 minutes, or until very thick. Turn the polenta out onto two dinner plates, spreading it into a thin circle all the way to the rims of the plates. Let it cool for at least 1 hour. It will become very firm. Cut the polenta into cubes or dice, and proceed with the recipe below. NOTE: For an even crisper result, let the cut pieces "air out" for about an hour before frying. Make the Hash: Place a 10-inch saute pan over medium-high heat for about 2 minutes. Add 1 tablespoon of the oil, wait another 10 seconds or so, then swirl to coat the pan. You can also melt in some butter for a richer flavor. Add the Polenta Pieces (you should hear a nice sizzle on contact), and saute in a single layer for a good 12 to 15 minutes, loosening and moving them around every 5 minutes with a metal spatula to keep them from sticking. They will crumble somewhat, which is actually desirable, as it makes a crisper result. Do not move the pieces any more often than every 5 minutes; letting them sit over the heat is what gets them crisp. If the polenta appears to be sticking, push it to one side, lightly spray the pan with nonstick spray -- or add a little more olive oil -- and resume sauteing until all surfaces are golden. When the polenta turns golden, move it over to one side of the pan, and pour in a little additional oil. Add the onions, jalapeno , and chile powder, and saute for 8 to 10 minutes, or until the onions are very soft. Stir in the garlic , and saute for another 5 minutes. Push the polenta pieces back into the center, and mix everything together in the pan, still over the heat. Gently stir in the corn, tomatoes , and black beans , and cook just until heated through. (Be careful not to break the beans as you stir. The dish looks nicer if they remain whole.) Serve hot or warm, with salsa if desired. Yield: 4 to 6 servings Recipe Source: Mollie Katzen's Sunlight Cafe by Mollie Katzen (Hyperion) Reprinted with permission.