That can only be done if the add-on itself is set up to do that.

Add-on questions should be posted in the add-ons forum; https://discourse.mozilla-community.org/c/add-ons

One possibility would be to create a program-style shortcut instead of a URL shortcut. There are two research steps first:

(1) Find the path to your Firefox program (firefox.exe). For example, you can find that on the Troubleshooting Information page. Either:

• "3-bar" menu button > Help > More Troubleshooting Information
• (menu bar) Help > More Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, find the row titled Application Binary. It should list a path such as

C:\Program Files\Mozilla Firefox\firefox.exe

Got it?

(2) Find the URL of your extension page

This should be easy to copy from the address bar.

Once you have both elements: resize Firefox so you can see some clear desktop, and then:

Right-click a blank area of the desktop > New > Shortcut

Enter the path:

(A) Type " then paste the Application Binary path then type "

Most likely, at that point, you have:

"C:\Program Files\Mozilla Firefox\firefox.exe"

(B) Type a space then paste the URL of the extension page

Now it should look something like this:

"C:\Program Files\Mozilla Firefox\firefox.exe" moz-extension://bc22919a-d570-4194-bb19-626d77e55dda/manage.html

(C) Click Next and enter a useful label for your shortcut, such as the name of the extension, and then click Finish

Now you can test your shortcut. It should open a new tab to your extension page.

Success?

Note that you can also create a copy of an existing Firefox desktop shortcut and modify its properties and add the moz-extension:// link to its target field. Note the moz-extension:// are profile specific, so you would have to update the UUID if it gets changed for some reason (see also about:debugging).