Apologies if this is answered elsewhere. I'd like to write two simple scripts to open and close certain installed widgets. The reason is that I want to close certain widgets on shutdown, and open certain widgets on startup.

That is, one script will achieve the same as the following action:
-pressing and holding on the desktop; selecting 'Desktop menu'; selecting 'Add widget', selecting a particular widget to add; finally pressing 'Done'.

And the other script will achieve the same as the following action:
-pressing and holding on the desktop; selecting the 'close' button on a certain widget; pressing 'Done'.

You can use desktop activity manager
http://maemo.org/packages/view/actman/

or take a look at the source code to find out
how it adds or removes the widgets.