Assemblies have the same view capabilities as part file.
Parts are assembled in space orientation. If you pick "default" when adding a part, it orients the same as is does in its part mode.
You can define views from the "orient" dialog of the view UI. Click any flat surface or datum plane to set the "face" of the view and any surface or datum plane normal to the 1st selection to be the "top" direction.
Or am I completely off by how I am interpreting your question?