How to view Windows' equivalent of Unix Swap usage?

You can view this information by opening up the Resource Monitor and selecting the Memory tab:

"Used Physical Memory" is your RAM, while "Commit Charge" is the sum of RAM and the paging file, or the maximum available virtual memory. (This comes from a display of how much virtual memory windows has "committed" to being able to provide - the sum of every allocation request it has granted.)

Windows and Linux manage their paging/swap space differently, however. With Windows, a paging file with 0% utilization is not good for performance; rather, Windows will try to mirror every page from RAM onto the paging file if it can. This will allow it to quickly drop pages out of RAM when it needs to reuse them for something else. This is why Windows will try to create a paging file at least as big as the physical RAM you have installed on your machine. It's less of a swap file, and more of a backing store.