Make the dressing by combining all the ingredients in a bowl and whisk together. The sauce will keep in an airtight container in the fridge for 2-3 weeks.
Slice the zucchini flowers lengthwise, remove and discard the stamens (the pollen) carefully with your fingers.
Heat the oil in a wok or frying pan until smoking, then add the zucchini flowers and squash.
Stir-fry for 2-3 minutes on high heat until just tender, then turn the heat off and add the dressing. Stir to combine and serve immediately.
