For the past several releases the option of opening something in terminal by right clicking on the desktop, a file or a folder has been missing in MATE environment of Linux mint. This has been set by default. However you can enable that functionality by installing a package called caja-open-terminal.
sudo apt-get install caja-open-terminal
After installing the package, you will have “Open in terminal” as one of the options in the context menu when you right click on icons or certain locations.