The easiest way to remove a viewer from your Meeting is to turn on an Access Code (and provide that code only to the individuals who should have access).
When in your Meeting, look above the upper right corner of the slide area. Below your Meeting Link, you will see "access code: Off." Click on that area, and a pop-up will appear. Within the pop-up you can choose to assign a random numeric access code to your meeting, or choose a custom access code. The custom access code can be alphanumeric, so feel free to create whatever access code you'd like.
Once the Access Code has been enabled, everyone on your Meeting Link will no longer see your presentation and will instead see a screen prompting them to enter the Access Code. Those individuals who have your code will be able to provide it and resume access. Any individuals who you have NOT provided the Access Code to will no longer have access to your presentation.