Peel and devein shrimp. Cut scampi in half lengthwise and wash thoroughly under cold running water. In large pan, saute onion and garlic in oil. Add bay leaves and pepperoncini. Pour the plum tomatoes with their juices. Cover and simmer over medium low heat for 10 to 15 minutes. Add scampi and salt to taste. Pour in the wine, and simmer for 4 minutes covered. Arrange scampi on plate, pour over some of the cooking juices and garnish with the parsley.