In pot, lightly sauté onions in oil, until onions begin to get translucent (no need to cook onions through). Add tarragon. Add split peas, cayenne and water. Bring to boil. Gently simmer until tender, about 2 hours, adding water if necessary. For soup, desired final product will be peas lightly bound with water, easy to stir. For a pea puree side dish, a tighter mixture. Season with salt toward the end of cooking time. Remove from heat. Puree. Add orange juice and wine. Combine well. Correct seasoning.