Put the potatoes in a pot with a lid with enough water to cover them with the salt and oregano. Leave them until they are fully cooked but still firm.
Meanwhile in a large bowl mix the tomato juice, the ketchup, the lime juice, the orange juice, the hot sauce, the olives, and minced onions. Add a pinch of salt and check the flavor for seasoning. Adjust if necessary.
When the potatoes are done, drain them and rinse them with cold water, put them in the bowl with the rest of the ingredients. Add the cilantro and mix carefully.
Serve in small bowls or cups. Finish with slices of avocado.