1. First, prepare the batter. Put the rice flour, cornflour, sesame seeds, five-spice, salt and sugar into a large mixing bowl and stir well. Make a well in the centre of the dry ingredients then pour in the water. Stir until the mixture is evenly blended and there are no lumps in the batter. It should be fairly thick.
2. About 10 minutes before you will be ready to serve, peel the bananas and cut each one into 3 or 4 short lengths. Heat a 5-6cm depth of oil in a wok or deep heavy-based saucepan until hot. To test if the oil is hot enough, drop a little batter into the pan it should sizzle immediately.
3. Cook the fritters in batches. Dip the bananas pieces in the batter to coat all over, and then carefully lower into the hot oil. Fry for a few minutes until until golden brown all over, turning once. Remove and drain on a plate lined with kitchen paper. Keep warm, while you cook the rest of the fritters.
4. Dust the crisp hot fritters with icing sugar and serve straight away with a scoop of good-quality vanilla ice cream