Taking your subquery first:-
1) The following is cut from C:\winows\tips.txt:

[Windows Explorer Switches]
Windows Explorer switches are useful in creating rooted folders:
 
	Explorer [/e][,/root,<object>][[,/select],<sub object>]	

/e	Use Explorer view (scope and results pane view). The default is Open 
	view (results in pane view only).	
/root<object>	Specify the object in the "normal" name space that is used 
	as the root (top level) of this Explorer/Folder (i.e., local path 
	or UNC name). The default is the Desktop).	
/Select	The parent folder opens and the specified object is selected.
<sub object>	Specify the folder unless /select is used. The default is
	the root.	

Examples: Explorer /e, /root, \\Reports  opens an Explorer window at \\Reports.
	
	  Explorer /select, C:\Windows\Calc.exe  opens a folder at
		C:\Windows (or activates one that is currently open) and
		selects Calc.exe.	
	  Explorer /e, /root, \\Source\Internal\Design\Users\David\Archive
		opens a folder to the Archive folder above. This is a good
		way to create a dedicated, remote, documents archive 
		folder. A link to this folder 
		(\\Source\Internal\Design\ Users\David\Archive) can then be
		placed in the SendTo folder for quick routing of documents.

2) And, similarly from Personal Computer World, September 1997, p.221:

Explorer has four switches and two path parameters which can be used in various combinations.
Each is preceded by a forward slash and separated by commas.
1. The /e switch forces a two-paned view, as when you "explore", rather than "open" a folder, but only when a folder is specified.
Explorer.exe on its own opens two panes, with the C:\ drive expanded. The command Explorer.exe /e, C:\ does exactly the same,
although you can change the drive letter to expand other drives. Leave out the /e, and you get a single pane view.
2. The /n switch opens a new window, even if the folder is already open - you dont need to include this
if you use the /e switch as that opens a new window anyway.
3. The /root switch governs where you want to start from: use it with the /e switch to define the top level
of wher you want to explore; you cant go up beyond this ceiling. Its useful, for instance, when comparing
the contents of drives or moving files between them. If you set the drive letter as the root, e.g. Explorer.exe /e, /root,C:\ then you have a view
 like the old File Manager sub-windows. You can specify a folder to expand by adding a comma, then the folder name.
Explorer.exe /e,/root,C:\windows will expand the Windows branch in the left pane and show the contents of C:\windows in the right. Note that if
 you leave out the comma, the windows folder will be the root; you wont see anything higher or be able
 to navigate to other folders in C:\
4. Finally theres the /select switch. This selects whatever follows it without opening the branch, so
Explorer.exe /e,/root,C:\,/select,windows will show the contents of C:\ in both panes with the Windows folder highlighted
on the right. (Which is why you had: Explorer.exe /e,/select,C:\)

With regard to your SPECIFIC requirements, I'm afraid I know of no way to do what you want exactly
(bearing in mind the possibility of other undocumented switches, knowing MS!)
This is because when you right-click on the Start button, which is part of the Start MENU, you are automatically
assumed by explorer, to be AT, OR BELOW, that level, so explorer automatically opens up, and expands,
down to and including, C:\windows\Start Menu. Brilliant! (NOT!) Even using the techniques to follow,
in answer to your FIRST question, I know of no way round this.

HOWEVER, HAVE YOU CONSIDERED THAT JUST RIGHT-CLICKING ON "MY COMPUTER" AND CHOOSING EXPLORE, DOES
WHAT YOU WANT (I know this isnt what you specifically asked but its the best I can do, having messed
around with several options, above and below - please advise if any more success)
ALSO PCW 1998 (p.258) suggests a couple of sheareware programs which _might_ be of interest:
1. Start Menu Changer, by Alexey Vasilyev
2. TClock by Kasuto Sato

Finally, in answer to you FIRST question, you can edit the contents of the menu produced by right clicking on Start, in the 
following way (with the caveat above that it probably wont do you any good for your _specific_ problem):
1. Open up a folder on the desktop
2. Choose View, Options, File Types
3. Highlight "Folder" (NOT "file folder") and click edit
4. Create a new action, say explore2, in the usual/obvious way
5. click OK twice (or so)

One final point: At step 4 immediately above, you might be interested to know that you can change the
 default action from open to explore, so double-clicking folders will open them in explorer, rather than just on the desktop.