Place the potatoes in a large pot with enough lightly salted water to cover. Bring to a boil over medium-high heat, and cook until tender, but still firm. It will take about 20 minutes. Drain, cool and cut into bite-size pieces.
In a large salad bowl, whisk together the olive oil, garlic, and Dijon mustard. Add the cabbage, corn, red onion, red pepper, green pepper, yellow pepper, and cucumber. Add kidney beans, if desired. Mix in the cooled potatoes. Wash your hands, and use them to mix everything together until well coated with the dressing. Gently stir in the Romano cheese, and season with salt and pepper to taste. Chill for one hour before serving.