In a large bowl, combine flour, sugar, salt and baking powder in a large bowl.
In a small bowl, combine the banana with vanilla and water. Stir to combine. Add this to the dry ingredients and mix to form a thick batter. The consistency should be like muffin batter. Let it rest for 5 minutes.
Meanwhile, combine the cinnamon and sugar and mix to combine. Spread it on a plate.
In a small saucepan, heat sugar and water for the glaze. Cook until the ingredients coats the back of a wooden spoon. Add coconut milk, salt and vanilla. Cook another 2-3 minutes until the glaze starts to pull from the bottom of the saucepan.
Heat a large wok or deep skillet with enough oil for deep frying.
Using a tablespoon or a scoop, place in the hot oil for each donut. Reduce the flame to low and cook until golden brown on both sides.
Drain on paper towels for 1 minute. Roll in the cinnamon sugar.
Serve with the coconut glaze.