Wash the pumpkin thoroughly, peel it, and cut it into bite-sized pieces.
Place the sliced pumpkin in a steamer and steam for 15-20 minutes.
Transfer the cooked pumpkin to a bowl and mash it.
Finely chop onions, cucumbers, and apples, then add them to the bowl.
Add mayonnaise, salt, and pepper, and mix everything evenly.
Place the finished pumpkin salad on a plate to serve.