How to Make It
In a large bowl, toss the couscous with 1 teaspoon of salt. Stir in the water, cover with foil and let stand until the water is absorbed, about 15 minutes.
Meanwhile, in a small bowl, whisk the lemon juice with the cumin, garlic and lemon zest. Gradually whisk in the olive oil and season with salt and pepper.
Fluff the couscous with a fork. Add three-fourths of the dressing and the rosemary and let stand for 5 minutes. Stir in the plums.
In a large bowl, toss the mesclun with 2 tablespoons of the dressing. Transfer to a large platter. Mound the couscous on the mesclun and top with the sliced duck. Drizzle with the remaining dressing and serve right away.