Put rice in 400 ml boiling salted water, bring to the boil, cover and let it swell for about 20 minutes over a low heat. Meanwhile clean and wash spring onion and cut into rings.
Clean, wash and chop the peppers. Pour the tuna on a sieve, drain. Pluck fish apart with a fork. Wash chives, dab dry and cut into small rolls. Wash parsley, dab dry and chop finely.
Mix sour cream, salt, pepper, mustard and sugar. Rinse rice with cold water and drain well. Mix the rice, olives, tuna, peppers and spring onions. Pour mustard and sour cream over it, add herbs.
Mix the salad well. The salad tastes best if it can stand for 3-4 hours. Arrange on a plate.