Cook pasta according to package directions. Drain pasta; rinse with cold water. Drain again.
In a large mixing bowl combine pasta, ham, cheese, peas, celery, onion, and pimiento. Toss gently to mix.
For dressing, in a small mixing bowl stir together mayonnaise or salad dressing, pickle relish or chopped pickle, milk, and pepper. Pour dressing over pasta mixture. Toss to coat. Cover and chill for 4 to 24 hours.
Just before serving, stir in milk, if necessary. Spoon pasta mixture into a serving bowl.
Arrange cherry tomato halves around the edge of bowl. If desired, garnish with parsley. Makes 4 main-dish servings.