How to link to a Google Scholar entry?
Looking at the website you cited (matt-koehler.com/vita) He is evidently just linking to the cluster page.

Here is how I was able to recreate that sort of link:

Go to your Google Scholar profile. Click on the paper you want to link. The pop-up window you mention will appear. At the bottom of the pop-up, there is a link that says "All X versions" where X is some number. That link will contain the URL you want.