Yellow
Hey there. What I can do is to listen for the new tabs opening, and when the user opens a new tab, it will automatically close it. Since there is no explicit "disable new tabs" API in the chrome. On the note of opening all links in the same tab, that can be done by manipulating the DOM. Override every "a" tag and its "target" attribute to be set on "self". For example, when it is set to "_blank", that means that link is opened in a new tab, and "self" means open in the same tab as the webpage.
Anyways, feel free to hit me up so we can talk more about this. I am very responsive. All the best