You can hide the "most views" navigation element by adding the following snippet to the stylesheet of your theme:
.qa-nav-sub-views {
display: none;
}
Disabling the URL parameter "sort=views" entirely might be accomplished by overriding the function qa_get() and changing a return value "views" to null:
function qa_get($field) {
$val = qa_get_base($field);
return ($field === 'sort' and $val === 'views') ? null : $val;
}
I cannot guarantee that this won't have side effects, so use at your own risk.
And since you went out of your way to downvote my answer I'll leave it to you to figure out where to put that function. Have fun.