In a covered pot, steam clams and mussels with white wine until shells open, about 5 minutes. Strain and reserve broth.
Meanwhile, fill a stockpot with water and bring to a rolling boil. Add salt and orzo and boil for about 8 minutes. Carefully drain in a colander (the orzo can slip through colander holes if they are too big).
Heat oil in a large skillet or paella pan over moderate heat. Add onions and saute until soft, about 10 minutes. Add garlic and saute another 2 minutes to release aromas. Stir in bell peppers, chiles and tomatoes and cook another 2 to 3 minutes, or until slightly softened. Stir in shrimp and cook until shrimp turn pinkorange, about 1 to 2 minutes. Add peas, saffron, oregano, coriander and reserved broth from mussels and clams. Simmer for a few minutes.
Stir in orzo and heat through, adding clam juice or fish stock as needed to make a soupy texture. Stir in clams and mussels. Adjust seasoning.
To serve, spoon hot paella into serving bowls and serve immediately.
c.1997, M.S. Milliken & S. Feniger, all rights reserved