Green mango adds refreshing tartness to summer salads. Tart green apple also works really well here.
Jicama, also known as yam bean, is available from Asian supermarkets. Roasted chilli flakes and roasted sticky rice powder are available from Thai grocers. To make your own roasted chilli flakes, dry-roast whole dried red chillies in a wok over medium heat until browned and smoky, then finely crush with a mortar and pestle. To dry-roast spices, cook the spices in a dry pan, stirring continuously over medium-high heat until they're fragrant. To make roasted sticky rice powder, dry-roast sticky rice in a wok overmedium heat until toasted and golden, then finely crush with a mortar and pestle.