Bring the water to the boil. Add salt, pour in the rice and stir well. Cover and cook gently for 45 minutes. The rice should be cooked but still retain some bite. Pour it into a sieve and stop the cooking by rinsing under cold running water, drain thoroughly and leave to cool.
Make the vinaigrette: place the mustard in a bowl, then add the cider vinegar, sunflower oil, maple syrup and soy sauce. Blend well and season with salt and pepper.
Arrange the cold wild rice in a salad dish and spread the sliced smoked salmon over it. Drizzle over the sauce and sprinkle with sesame seeds and some ground pepper.