Heat oven to 200C/fan 180C/gas 6. Score the skin of the duck breasts and season. Heat a non-stick frying pan over a high heat, add the duck, skin-side down, and cook for 4 mins or until the skin is crisp. Turn over and quickly brown the underside, then transfer to a baking tray.
Mix the dressing ingredients together and spoon all but 2 tbsp of it over the duck. Roast the duck for 10 mins for pink, longer if you prefer. Remove from the oven and allow to rest for 4 mins, then slice into strips. 3 Toss together the salad, tomatoes, spring onions and duck slices. Drizzle over the remaining dressing and serve.