1. Cook pasta according to package directions, preferably al dente (firm to the bite). Drain; rinse with cold water and drain again.
2. In a large mixing bowl combine pasta, ham, cheese, peas, celery, onion and pimiento. Toss gently to combine.
3. For dressing, in a small mixing bowl stir together mayonnaise or salad dressing, pickle relish or chopped pickle, salt and pepper. Pour dressing over pasta mixture. Toss to coat. Cover and chill for 4 hours or overnight.
4. Just before serving, stir in milk, if necessary. Spoon pasta mixture into a serving bowl. Arrange cherry tomato halves around edge of bowl. Lightly sprinkle with snipped parsley over top of salad, if desired.