Bring a large pot of well-salted water to a boil. Cook pasta according to package directions until just al dente, about 8 to 10 minutes. Drain and rinse under cold running water until fully cooled. Let drain completely in the colander.

While pasta cooks, dice the bell peppers, red onion, and cucumber. Grate the carrots. Thaw frozen corn and pat all vegetables dry to prevent a watery salad.

In a small bowl, whisk together the mayonnaise, sour cream or Greek yogurt, mustard, lemon juice, salt, and pepper until smooth. Taste and adjust seasoning before adding to the salad.

In a large bowl, combine the cooled pasta, ham if using, carrots, corn, bell pepper, onion, and cucumber. Pour the dressing over everything and toss gently until well coated. Start with three-quarters of the dressing and add the rest as needed.

Cover and refrigerate for at least 30 minutes before serving. Garnish with fresh parsley or dill just before serving.