Bring 3 cups water to a boil in a saucepan. Stir in the couscous, cover, remove from the heat, and set aside for 5 minutes. Transfer the couscous to a large bowl and fold in the oil, tossing with a fork as the couscous cools to keep the grains from clumping. When the couscous has cooled, fold in the remaining ingredients. Transfer to a large serving bowl.