The solution for this is pretty simple, i fugured it out.
What a need to do is find some factor to apply to the position. This factor can be found takin the atual ColorImageFormat of the Kinect and dividing by the desired size, example:
Lets say i am working with the RgbResolution640x480Fps30
format and my Image (ColorViewer) have 220x240. So, lets find the factor for X:
double factorX = (640 / 220); // the factor is 2.90909090...
And the factor for y:
double factorY = (480/ 240); // the factor is 2...
Now, i adjust the position of the ellipse using this factor.
Canvas.SetLeft(elipseHead, (handColorPoint.X / (2.909090)) - (elipseHead.Width / 2));
Canvas.SetTop(elipseHead, (handColorPoint.Y / (2)) - (elipseHead.Height / 2));