Unfortunately, there are no PC versions of Snapseed at the moment. All you can do is access it from the Google Play Store or IOS.
There are third-party apps that provide alternatives for photo editing with mobile features such as Flare and Vignette that work on PCs, but they don’t have the same capabilities as Snapseed.
You can also install an interactive web browser app like Remix OS Player which allows you to use a mobile device as a mouse and keyboard. It allows you to play Android games on your computer via USB cable, too!