Fry chicken breasts, cool and slice finely, salt and sprinkle with chopped tarragon. Cut strawberries into 4 parts, season with pepper and drizzle with lemon juice. Cut green onions into rings. Mix the vinegar, port wine, mustard and vegetable oil. Place salad leaves on the plate, then chicken, greased with sauce, sprinkle with green onions and strawberries, pout the remaining sauce and serve.