Bring a saucepan of lightly salted water to a boil. Add the macaroni and cook until tender, about 7 minutes. Rinse under cold running water, then drain well and pat lightly with paper towels.
In a large bowl, stir together the macaroni, pickles, cheese, tuna, mayonnaise and mustard. Season with a splash of pickle juice, salt and pepper. Cover, and refrigerate for at least 30 minutes before serving.