I've done a couple of small projects.

I use the teensy, just because it works as a HID out of the box (the Arduino Leonardo does too, but I don't have experience with that). EDIT: other Arduinos can be made to function as HIDs too, they just don't do it out of the box, and I have no experience with doing this.

Once you have set your device to send keystrokes, which is very easy, I suggest having it send a specific hotkey combination, then using a program like Autohotkey to monitor for the hotkey combination, and then take the appropriate action. Autohotkey is very easy to program, and pretty powerful too. If you can do X on your computer, you can script it in Autohotkey too.

A simple example: In work, I took a Staples Easy Button, and connected a Teensy to the button. Then I have a USB cable going from the Teensy to my PC. When the big red button is pressed, the Teensy sends a "Windows key-and-J" keystroke to my computer. When autohotkey picks up the Win-J combination, it first puts me on break code in our phone software by activating the https://omglz.com phone software https://omegle.love window, then clicking in a specific position. Then autohotkey sends a Win-L keystroke to lock my computer.

Autohotkey is great. It makes manipulating windows/whatever omegle.2yu.co really easy.

tl:dr Have your Arduino send a unique keystroke, then have Autohotkey do the heavy window manipulation