Put the salmon skin-side down on a large baking sheet. Mix the pomegranate molasses, olive oil, mint, pine nuts and the lime juice with a good pinch of salt and a few grinds of black pepper in a small bowl, then brush the mixture all over the flesh of the salmon. Add the sliced lime on top and chill for at least 20 mins, or overnight if you can.
Heat the oven to 200°C. Mix the pomegranate seeds with the parsley, mint, red onion, remaining lime juice and olive oil in a bowl, and set aside.
Remove the mint and roast the salmon, uncovered, for 10-12 mins, until cooked through. You can check this by poking a knife into the fillet and ensuring the fish flakes easily.
Top the salmon with the dressing, and serve with couscous or steamed green veg, if desired.