1) If the couscous is instant, follow the instructions on the packet.
2) For non-instant couscous, place the couscous into a large bowl. Fill a pot or large pasta pot 3/4 of the way with water. Bring water to a boil. Pour the couscous into the boiling water and stir. Cook for 7 to 8 mins until the couscous is tender. Drain the couscous and toss in preserved lemon and coriander. Season with salt and pepper.
3) For the quick preserved lemon: Slice 2 lemons into 0.5cm slices, lay out on a plate and salt on 1 side. Turn over and salt the other. Stack on top of themselves and let sit for 20 mins in a baking dish. Rinse gently with cold water and dice into 1cm pieces.