Clean the clams, discarding any broken shells or that won’t close when you tap them. Place them in a large bowl of cold water with the cornmeal for 30 minutes. Drain, rinse, and wash away any sand.
Bring a large pot of salted water to a boil. Cook spaghetti 3-4 minutes if fresh or according to instructions on the package.
Meanwhile, in a saute’ pan, heat olive oil over low heat. Add the garlic and the peperoncini, and cook until the garlic is fragrant. Raise the heat to medium and add the clams., shaking the pan and stirring to coat them in the oil and garlic.
Add salt and pepper, then parsley and toss to coat the clams again. Put the lid on. Cover the pan and cook, shaking the pan every so often until the clams are open and cooked, about 3 minutes. Discard any that don’t open.
When the pasta and clams are done, drain the spaghetti, and add to the pan with the clams. Toss.