Mix the rice flour with salt, corn starch, spice mixture, sesame seeds and sugar. Make a small well in the middle and pour in the water. Mix into a smooth, thick batter.
Peel the bananas, cutting each into 3-4 pieces.
Pour oil into a wok (or heavy-based saucepan) - it should be deep. When the oil is hot (i.e. a small piece of dough immediately sizzles), dip the banana pieces in the batter and fry in the hot oil until light brown, while turning once.
Drain on a paper towel and serve warm.
If you want a candied (sticky) version, replace the sesame seeds with 1 teaspoon of sesame oil in the batter, leaving out the sugar.
Make a light caramel sauce with 150 of sugar, 2 Tbsps water and 2 Tbsps sesame seeds.
Fry the banana piece as above, then coat them in the warm caramel sauce and cool on a rack.