Cook macaroni according to directions on the box in salted water, drain and cool. Toss with a little sunflower oil to keep the pasta from sticking together, chill.
Chop all vegetables and place in a large bowl with the chilled macaroni, mix well.
In a medium bowl, whisk together the mayonnaise, mustard, sugar, vinegar, and season, to taste with salt and pepper. Pour the dressing over the salad and stir to combine. Chill for several hours or overnight. Store covered in the refrigerator, for up to 5 days.
Serves 6