Cook the potatoes with their skin on until they are cooked through. Let cool, peel and cut into bite-sized pieces.
Chop the onion into cubes and cut the chilli pepper into small pieces. Peel the cucumber. Cut the cucumber and tomatoes into cubes. Press or finely chop the garlic, sprinkle a pinch of salt on it and mash it again with the flat side of the knife so that the juice comes out.
Fry the onions until they are translucent, then add the chilli pieces and fry briefly. Add the cucumber and tomatoes and simmer briefly. Then add the garlic and let the sauce simmer for 5 minutes. Pour in the vegetable stock, add 3 tablespoons of tomato paste and 2 tablespoons of mustard, stir everything and let it boil until the sauce is creamy. Depending on the heat you want, add an appropriate amount of Tabasco and season the sauce with salt, pepper, oregano, basil and thyme.
Finally, mix in the potato pieces and only let them cook for a short time so that they don`t overcook.
Garnish with chilli flakes to serve. But be careful: They also give you some spice!