Combine the zucchini or squash, dry chickpeas, turmeric and water in a pressure cooker. Seal the pressure cooker and cook at high pressure for about 20 minutes. Reduce heat to low and simmer another 3 minutes. Remove from heat and allow the pressure to release naturally.
Heat the oil in a large saucepan. Fry the chilli flakes and cumin seeds until the seeds begin to splutter; add the ginger and garlic to the mixture and cook together 1 minute more. Add the zucchini and chickpea mixture, sugar and salt to the saucepan; bring to a boil, reduce heat to low, and cook another 5 minutes before serving.