In a medium bowl, combine banana, lemon juice, sugar, cornstarch and cinnamon and mix well, smashing bananas slightly with the back of a wooden spoon.
Lay out egg roll wrappers on a large work surface. Working with one wrapper at a time, spread 1 tablespoon nutella across the wrapper, leaving about ¼-inch border around all edges. Spoon 3 tablespoons banana mixture across the middle of the wrapper and lightly brush all the edges with water. Position the wrapper so that one point (corner) is closest to you. Fold that corner up just enough to cover the filling. Fold each side over to meet in the middle and roll up from the bottom. Brush final corner with water, and press lightly to seal. Transfer to a baking sheet seam side down. Repeat with remaining wrappers, nutella and filling.
Heat about ¼-inch oil in a large skillet. Fry egg rolls 6 to 9 minutes or until golden brown on all sides, using tongs to brown evenly. Remove and let drain on paper towels.
To serve, dust with confectioner’s sugar and cut in half.