I have the results of a mesh but one dimension is significantly larger than the other 2 dimensions. Is it possible to scale down this dimension for viewing of the mesh with ABAQUS/Viewer?

Yes this is possible. In the Visualization module click on the Common Contour Plot Options icon.
In the dialogue box which pops up select the Other tab and check the box marked scale. Use a scale factor to reduce the dimension only in the length direction and this only affects as it is only a viewing scale.