Mix half the lime juice, the lime zest, yoghurt and half the coriander with a litle water and season. Pour boiling water over the bulgar wheat, cover with cling film and leave for 10 mins until the water has been absorbed. Rub the cajun seasoning into the salmon. Heat 1 tsp of oil in a frying pan and cook the salmon skin-side down for 4 minutes until the skin is crisp, then cook flesh-side down for 3 minutes until cooked through. Mix the herbs, red onion and remaining lime juice with the bulgar wheat and serve alongside the salmon and dressing.