how to delete someone from all gitlab projects code example

Example: how to delete a project in gitlab

Go to the project page
Select "Settings"
Select the "General" section (you must be in the repository you want to delete to delete it)
If you have enough rights, then at the bottom of the page will be a button for "Advanced settings" (i.e. project settings that may result in data loss) or "Remove project" (in newer GitLab versions)
Push this button and follow the instructions