Bring a large saucepan of salted water to a boil. Add couscous and cook until tender, 8-10 minutes. Drain.
While the couscous cooks, in a large bowl, whisk the oil, mustard, honey, lemon zest, lemon juice, 1/2 teaspoon of salt, and 1/4 teaspoon pepper. Add the drained couscous to the dressing and mix well.
Stir in the cucumber, tomato, herbs, walnuts and raisins. Taste for seasoning and adjust with salt and/or pepper as needed. Enjoy warm or cover then refrigerate until cool, about 1 hour.