If using fresh beets, boil them for an hour or until they're tender and can be easily pierced with a knife or fork. If using canned beets, just drain them from any liquid.
Do not boil the beets with any other vegetable as everything will turn pink. So in a different pot, boil potatoes and carrots together until tender (about half an hour). Make sure not to overcook the potatoes as they need to hold their shape when they're sliced.
After you cook the vegetables, drain them from water and set them aside to cool down completely before you peel and chop them.
Peel the cooked vegetables, then dice them. Also, dice the onion and the pickles.
To prevent the beets from coloring the other vegetables, add 1 tablespoon of sunflower or olive oil and coat them in the oil.
Mix all vegetables together along with the kidney beans if using, and add 2 tablespoons of olive oil and 1 tablespoon of white or apple cider vinegar. Season with salt and ground black pepper and give it a good mix.
Garnish the salad with chopped green onions and store in the fridge until you're ready to serve.