Break the spaghetti into small pieces and cook according to the instructions on the package. Cut the onions, cucumber and apples into small cubes. Drain the kidney beans, corn and mushrooms. Halve the mushrooms. Put all the cut and drained ingredients in a large bowl.
Add mayonnaise, tomato ketchup, oregano, pepper, salt and curry powder and stir. Add the cooled spagetti and also add the tomatoes with the juice pressed through a sieve. Stir the whole thing again. Can be served immediately.