Place one slice of banana in the middle of the wonton. Place one teaspoon of peanut butter on top of the banana. Moisten all the outer edges of the wonton and fold together like a triangle. Gently work any air bubbles out and press moistened edges together.
Heat an inch of canola oil in a large saucepan until crackling. Do NOT boil. Fry stuffed wontons for about 15-20 seconds, flip over and fry another 15-20 seconds. Stay real close because they cook real fast.
Remove to paper towels and sprinkle with powdered sugar.