We have an additional team in “Browse Teams” that must have been made by another user in our organization. We did not join this team but the creator of the team shows whenever we are trying to assign tasks and we do not want to mistakenly assign tasks to this user who is not part of our team.
Is there a way to remove this team or user so they are not visible in our portal.
Hi @Christopher_Alworth , welcome to the forum 
I’m not sure what you refer to as ‘our portal’ but it’s important to understand that all members of your Asana organization will show up in the assignee field when you search for anyone. This is irrelevant to members of a particular team that the project is within.
There isn’t anything you can do about this, except for actually removing the member from your Asana organization, if they are no longer part of your company/team.
As for the Team they created; all non-private teams of an Asana organization will show up in the Browse teams page. If there is a team created by a member who has been removed from your Asana organization (and no one else is a Team Admin) then you will need to request from Asana support for them to delete that team (and all projects within it).
You may also want to vote on the below thread, although I personally doubt Asana would ever implement this, otherwise how would you assign tasks to people beyond your team or project?