In a medium bowl, beat the eggs with fish sauce and set aside.
Mix the tapioca flour, rice flour and a pinch of salt in 125ml water to make a very thin batter. In a large wok, heat 1 teaspoon oil until smoking hot. Pour in the batter and let it set.
Pour the eggs over and when it is almost set, mix everything together. Make a well in the centre by pushing the egg and batter mixture to the sides of the wok. Add the remaining oil and stir in the garlic until fragrant. Add the chilli paste and oysters. Season with salt and pepper to taste. Toss until heated through.
Turn onto a serving platter and garnish with coriander sprigs. Serve with bottled chilli sauce mixed with vinegar to taste.