Cook rice according to package directions.
Preheat extra-virgin olive oil in a skillet over medium high heat. Season the chicken with salt and pepper. Brown and cook chicken, 5 minutes on each side. Remove chicken to a plate and cover. Reduce heat a bit. Add vinegar and water, scrape up pan drippings. Stir in tomato paste, cream, half-and-half or sour cream and tarragon. Remove from heat.
Toss nuts and parsley with cooked rice. Slice chicken on an angle and arrange on a bed of rice. Top with sauce and serve. Garnish plate with edible flowers and tarragon.