Robyn Eckhardt writes: Oyster omelette, fresh oysters fried with beaten eggs and usually bound with some sort of starch solution, is an Asian street food staple. I had my first taste in Hong Kong about 15 years ago -- the dish's flavorless bivalves and strangely gummy texture left me underwhelmed. Since then I've sampled -- usually at the goading of well-meaning local gourmands -- various versions, from Shanghai (mushy oysters) to Penang (nice char, but an awful lot of grease), and I remained unimpressed. Until last June, when we ate our way around Tainan, Taiwan's unofficial xiao chi ('small eats', ie 'snack') capital. On Guohe Jie, ...