I've posted this question before and someone kindly responded with exactly what I was looking for.
What I am looking for is a standard SAP program, run via SE38, where you enter a table name, e.g. VBAK and it produces a nice report documenting the column definitions.
If no one knows the answer, can someone at least tell me how to find the questions I have posted in the past and the answers I received? It used to be called "Control Panel".