1. For the salad: Cook the couscous as per packet instructions and allow to cool.
2. For the dressing: Combine all the ingredients in a jar and shake well until emulsified.
3. To assemble the salad: Tip the cooled couscous into a large bowl and fluff with a fork to break up any lumps. Add the remaining salad ingredients, pour the dressing over, and mix gently until just combined.
4. Serve immediately, or refrigerate.