Heat oil in heavy Dutch oven over low heat. Add onion, leeks, and celery. Cover and cook until tender, about 15 minutes. Add garlic and oregano, cook another 10 minutes then add tomatoes, breaking up with a spoon. Blend in the clam juice, wine, chili paste*, cumin, salt and cayenne. Bring to a boil, skimming occasionally. Reduce heat and simmer, partially covered, for about 1 hour, skimming. Mix in bell peppers. Simmer uncovered for 20 minutes. Cool. Refrigerate overnight. Bring chili to a boil. Adjust heat so that liquid simmers briskly. Skim well and adjust seasonings. Add clams and mussels. Cover and cook until shellfish open, 5 to 10 minutes. Discard any that do not open. Gently stir in scrod and shrimp. Cover and simmer for a minute. Add scallops, cover and simmer until fish is just opaque, about 2 minutes. Ladle chili into bowls. Top with cilantro. "Santa Cruz Red Chili Paste" is available from The Santa Cruz Chili and Spice Co., P.O. Box 177, Tumacacori, AZ 65640.