There are at least 3 options:
[ul][li]Insert -> Curve from bodies -> Section[/li]
[li]Insert -> Curve from Bodies -> Intersect[/li]
[li]View -> Section -> new section...[/li][/ul]
If you don't see one (or more) of these options in your menu, you may have to use the customize tool to add it or change to a role that includes it by default (such as one with full menus).