In a large soup pot, heat olive oil until smoking. Add onions, peppers, potatoes and leek and cook until light golden brown, about 8 to 10 minutes. Add 1 cup salsa Vizcaya and fish stock and bring to a boil. Lower heat and simmer 15 minutes. Season bonito and drop into broth. Return to boil, lower heat and simmer 4 to 5 minutes and serve.
