In a medium-sized mixing bowl, combine rice flour, sugar, toasted sesame seeds, salt, baking powder and shredded coconut. Add water and stir until well combined.
If using plantains, peel and cut them crosswise into 3 equal sections, then slice each section horizontally into 4 pieces. If using namwa bananas, peel and cut lengthwise into ¼-inch thick pieces.
Add about 1½ inches of oil to a pot and heat to about 325℉ (160℃). Dip the bananas into the batter and fry for about 5 minutes, until they are a deep brown colour. Maintain the frying temperature below 350℉ (175℃). When done, let drain on paper towel or a rack. Note: Based on your first batch, you can decide if you want a thicker or thinner coating by adding more flour or water.
Let bananas cool for several minutes before serving and the coating will crisp up once cooled.
Serve as soon as they are cool and crisp.