Prepare a vinaigrette with oil, a whole clove of garlic, lemon juice, parsley, salt, and pepper and let sit in the refrigerator for 1 hour. Boil the rice, dice the celery, and cut the octopus into small pieces. Let the rice cool and transfer it to a salad bowl, add the octopus, celery and olives and finally the vinagrette. Stir and serve.