Heat the oil in a frying pan over a medium heat. Add the couscous and toast for 5 minutes, or until the grains turn a light golden brown. Tip the couscous into a deep large bowl. Pour over 250 ml boiling water, then cover with a plate and let sit for 10 minutes. Remove the plastic and fluff the grains using a fork, until all the grains are separated and there are no clumps. Add all the remaining ingredients and season with salt flakes and freshly ground black pepper. Mix carefully but thoroughly, then taste – you may need to add an extra splash of olive oil to moisten the couscous a little. Serve.