You could also do it with nurbs, do a cylinder, then using the curve tool just create a rectangle (don't forget to close the curve at open/close curve) . Now you have to go to "edit nurbs -> project curves on surfaces", do it in the view port you created the rectangle, so it will project the rectangle by the view you are look, you can change in the settings...

Now all you've got to do is trim surfaces, select the cylinder part you want to keep and press enter.

Now convert your nurbs cylinder to poly.