SharePoint Online: PowerShell to List Deleted Sites

Requirement: Find All Deleted Site Collections in SharePoint Online

How to Get Deleted Sites in SharePoint Online?
Deleted site collection are sent to recycle bin in SharePoint Online and stays there for 92 days until they purged permanently. To check if a site collection is deleted and exists in recycle bin,

• Login to SharePoint Online Admin Center >> Click on "Deleted Sites" link from left navigation (In classic Admin Center, Go to "Site Collections" link from the left navigation and click on "Recycle Bin" Icon)
  

From here, You can either restore or permanently delete the site collection!

PowerShell to Get Deleted Site Collections in SharePoint Online:
Using SharePoint Online Management Shell, you can get a list of deleted site collections as:

$AdminSiteURL = "https://crescenttech-admin.sharepoint.com"
  
#Connect to SharePoint Online
Connect-SPOService -URL $AdminSiteURL -Credential (Get-Credential)
 
#Get all Deleted Sites
Get-SPODeletedSite

This lists all deleted sites

PnP PowerShell Get Deleted Sites in SharePoint Online
Similarly, you can get all deleted sites from SharePoint Online tenant recycle bin using PnP PowerShell too. Here is the PnP PowerShell to list deleted sites in SharePoint Online:

#Config Variables
$TenantURL = "https://crescenttech-admin.sharepoint.com"

#Connect to PnP Online
Connect-PnPOnline -Url $TenantURL -Credentials (Get-Credential)
 
#Get All Deleted Sites from Recycle Bin
Get-PnPTenantRecycleBinItem

How to check who deleted SharePoint Online site?
To find out who has deleted a SharePoint Online site collection, do the following:

• Go to Office 365 Security & Compliance Center at https://protection.office.com/
• Expand Search >> Audit Log Search Select the Activities as "Deleted site" and set the date parameters accordingly and hit search. 
• This will get you all sites deleted along with the user name who has deleted the site.
  

Please note, sites may be deleted as part of site policies, Office 365 group deletion, etc.