Cook the cracked wheat according to the instructions on the packet. Stir through the oil and set aside.
Stir the trout into the cooled cracked wheat, then add the cucumber, spinach, red onion, lentils and peas.
Make the dressing by mixing together the lemon rind and juice, poppy seeds and dill. Season the dressing to taste and just before serving drizzle it over the salad.