You can find your Resource Groups by hovering over Manage in the Top Navigation Menu, and then selecting Manage Resources. This will take you to the Resource Management page, which lists all Resource Groups you can delete.
If you're looking to delete a specific Resource Group, you can filter your results by duration, skill level, skills used, privacy settings, and Organization, or search by title using the search bar provided on the page.
You can delete a Resource Group by clicking the Manage dropdown under its listing.