Clean and wash the lettuce and watercress and drain well. Clean, wash and quarter the radishes. Clean, peel and cut kohlrabi into large sticks. Clean, wash and cut spring onions into rings.
Wash the meat, dab dry and cut into 8 medallions. Season with salt and pepper. Heat 1 tablespoon of oil in a frying pan and fry the meat for 3-4 minutes on each side. Whisk vinegar with salt, pepper and sugar.
Stir in 5 tablespoons of oil in a thin stream. Season once again. Mix the salad ingredients with the vinaigrette. Serve with the turkey medallions.