How do I manage / delete my Azure logic app connections
Reference MSDN blog
https://blogs.msdn.microsoft.com/logicapps/2016/04/13/browsing-api-connections-in-the-azure-portal/
Using Powershell to manage connections https://blogs.msdn.microsoft.com/logicapps/2016/03/18/using-powershell-to-manage-api-connections/
There is a first class UI support also available now in Azure Portal
Update: connections are now supported in the resource explorer
Let me know if this helps.
For sake of completeness, you can access the API connections associated to your Logic App from the options menu: