Heat the oil in a saucepan over medium heat. Add the couscous and pistachios and cook, stirring, until toasted and light golden brown, about 7 minutes. Add the water, season with salt and pepper, to taste, and bring to a boil. Reduce the heat to a simmer, cover, and cook until the liquid is absorbed, about 10 minutes.
Remove the lid, stir in the apricots and scallions, taste, and adjust the seasoning. Transfer the couscous to a serving bowl and serve warm with a little more lemon oil drizzled over the top, if desired.