Heat oil in a large, heavy saucepan set over medium heat.  When hot, add onion, carrot, and celery and sauté until softened—3 to 4 minutes.  Add rice, saffron, wine and stock and bring to a simmer.  Season with 1 teaspoon salt.  Bring mixture to a simmer, then reduce heat.  Cover and cook at a simmer until vegetables and rice are soft, for about 20 minutes.  Remove from heat and let cool for 10 minutes.  Puree the soup in batches in a food processor or blender and return it to the pot.  Stir in the cream.  Set soup over low heat and, when mixture comes to a simmer, add shrimp, chorizo, peas, and, if desired, chicken.  Cook until shrimp have turned pink and curled, for about 3 minutes.  Do not overcook or shrimp will become tough.  Taste soup and season with salt, as needed.  Garnish with a sprinkle of chives.