Blend onion/garlic and chili, in separate batches. Use some chili padi for heat.
Stir fry onion/garlic in oil
Add in belachan
Sugar to taste
(salt not needed since the belachan is salty)
The sambal can be used as a condiment to meals. Or for sambal kangkong, fry the veg till soft then add sambal to the wok to stir through.