Bring a medium saucepan of salted water to a boil. Add couscous and cook until tender, 8-10 minutes. Drain then add to a large bowl. Meanwhile, make the dressing. Whisk lemon juice, olive oil, honey, preserved lemon and basil together until it looks thick and blended. Season to taste with salt and fresh ground black pepper (we add a generous pinch of each). Toss the cooked and drained couscous with the dressing then set aside for 5 minutes, stirring occasionally, until cooled slightly. Finish the salad by adding the arugula, cucumbers and feta. Toss well then serve.