Remove pumpkin seeds and trim off the slimy, stringy parts that are attached to the seeds. Peeling is optional if you use calabaza or kabocha. Most of the time, in Thailand, the peel is left on for texture and to help pumpkin pieces hold their shape somewhat better. But if you don't like the texture of cooked pumpkin peels, you can remove the peel. Cut pumpkin pulp into bite-sized chunks of roughly the same size.