For dressing, in a blender container or food processor bowl combine low-fat cottage cheese, the 2 tablespoons milk, and tomato paste. Cover. Blend or process until smooth. Transfer to a small bowl. Stir in red pepper or pimiento, green onion, salt, pepper, and enough milk to make desired consistency. Cover and chill until serving time.
In a large bowl toss together romaine, red cabbage, and carrot. Divide among three salad plates. Arrange shrimp, crabmeat, and tomatoes on each plate. Drizzle with dressing. Garnish with carrot curls, if desired. Pass any remaining dressing. Makes 3 main-dish servings.