In a large frypan heat the oil add the onion then season with salt and cook over low heat stirring constantly until the onion is tender.
Add the capsicum, garlic and ginger then fry while stirring for a minute, until you can smell the aroma.
Add the curry paste and stir into the capsicum and onions, fry for a minute. Add coconut milk, water and soy sauce then stir and bring to a boil over low heat.
Cut the pumpkin, peel and remove the seeds. Cut into 2 cm cubes. Add to the sauce and simmer until the pumpkin is soft; about 20 minutes. Set aside from heat and add the lemon juice.
In the meantime, prepare the rice. Rinse several times in cold water. Pour 1 1/2 cups of cold water, cover and bring to a boil over high heat. Reduce heat to low and cook for 15 minutes. Let stand for 10 minutes without removing the lid.
Pour rice with pumpkin sauce and sprinkle with coriander.