Need a good "streaming" software for coding tutorials/workshops
I work on a Macintosh, but assume similar capabilities are available on other systems as well. My systems support multiple monitors and each monitor can show a separate desktop (or a section of a larger desktop). A window in one desktop can simply be dragged to another. If you just connect your regular monitor to one (physical or virtual) port and the projector to another, you will have what you want. If you don't have physical ports a junction/splitter may be required to support the multiple monitors so long as the software will support it. 

You could, possibly, have two monitors and a projector with the projector mirroring one of the monitors so as to make your own workflow easier. 

This assumes, of course, that you are interested in a face-to-face situation, not remote students.