Table of Contents Tab in upper left corner of Screen - Size and Visibility

You can get rid of them. For HTML5, execute this JavaScript on slide enter of the first slide or put it in the head of the html.

var tocBtn = document.getElementsByClassName('tocExpandCollapse');

tocBtn[0].style.display = 'none';

tocBtn[1].style.display = 'none';

Size is fixed, icon can be replaced by a custom one.

You cannot get rid of it, but you can make it invisible by replacing the standard icons (Settings for Table of Contents) by a transparent shape. It is possible to create a toggle button to open/close the TOC, which you can put on the master slide so that it is available on all slides. The action to be executed is pretty easy, look for more details in:

1 action = 5 Toggle Buttons - Captivate blog

In this video, I came up with a solution for this problem.

https://www.youtube.com/watch?v=vSRCpeEgY90&t=160s

I would place these buttons elsewhere than where I placed them in the video but this way you can have whatever sized buttons you wish and place them where you like.