Place 1 cup dry couscous in a heat proof bowl. Using a fork, stir in the salt and olive oil.
Pour the boiled water over the couscous and stir with a fork. Cover the bowl with a lid.
After 5 minutes, lift the lid and stir the couscous with a fork. Don't worry if you forget this step. The couscous will be fine.
After 10 minutes, remove the lid, stir the couscous with the fork again. Cover the bowl with a paper towel or plastic wrap and place it in the microwave. Heat for 30 seconds-1 minute depending on your microwave. Remove paper towel or plastic wrap, add the vinegar and stir with that fork one last time.