Trim and cut the aubergines into 2.5cm (1 inch) cubes. Sprinkle the cubes with salt and leave them in a sieve to drain for 20 minutes. Then rinse them under cold running water and pat them dry with kitchen paper.
Heat a wok or large frying-pan over a high heat until it is hot. Add the oil, and when it is very hot and slightly smoking, add the garlic, ginger and spring onions and stir-fry them for 30 seconds, then add the aubergines and continue to stir-fry for one minute. Then add the rest of the ingredients. Turn the heat down and cook uncovered for 10-15 minutes until the aubergine is tender, stirring occasionally.
Return the heat to high and continue to stir until the liquid has been reduced and has thickened slightly. Turn the mixture onto a serving dish and garnish with the chopped spring onions tops.