Preparation Cook orzo in pot of boiling salted water until just tender but still firm to bite, stirring occasionally. Drain. Rinse under cold water until cool. Drain well. Transfer to large bowl. Whisk lemon juice, 5 teaspoons marjoram, mustard, and lemon peel in small bowl. Whisk in olive oil. Set aside 2 tablespoons vinaigrette. Add remaining vinaigrette, cheese, onions, and olives to orzo; toss to coat. Season to taste with salt and pepper. Cover and let stand 2 hours to allow flavors to develop. (Can be made 1 day ahead. Cover and refrigerate salad and remaining vinaigrette separately.) Toss tomatoes with reserved vinaigrette. Season to taste with salt and pepper. Mix tomatoes into orzo. Sprinkle orzo with remaining 1 teaspoon marjoram and serve.
Preparation Cook orzo in pot of boiling salted water until just tender but still firm to bite, stirring occasionally. Drain. Rinse under cold water until cool. Drain well. Transfer to large bowl. Whisk lemon juice, 5 teaspoons marjoram, mustard, and lemon peel in small bowl. Whisk in olive oil. Set aside 2 tablespoons vinaigrette. Add remaining vinaigrette, cheese, onions, and olives to orzo; toss to coat. Season to taste with salt and pepper. Cover and let stand 2 hours to allow flavors to develop. (Can be made 1 day ahead. Cover and refrigerate salad and remaining vinaigrette separately.) Toss tomatoes with reserved vinaigrette. Season to taste with salt and pepper. Mix tomatoes into orzo. Sprinkle orzo with remaining 1 teaspoon marjoram and serve.