I want a simple paint app

While there are a ton of drawing apps out there, for young students I'd recommend something simple like:
Draw Kid - Drawing Pad for Kids
Paint Kid - Drawing Desk for Children

or Drawing, Painting & Sketch Pad Free ( if you need a little bit more )

or Autodesk SketchBook ( if you need even more )

 

I found that one while searching for a small simple word processor and remembered your thread:

http://www.growlybird.com/draw/index.html

It's for free and seems to be very simple.