Wildcards using get-azureaduser

Filtering in the Graph/Azure AD is crap, no other way of putting it. They recently added few minor improvements, but there's a looooong way to go still.

Anyway, for your specific scenario, it's probably best to use the Get-AzureADDomainNameReference cmdlet, which will return a list of object "matching" given domain. You can filter the results client-side to get just the users:

Get-AzureADDomainNameReference -Name michev.info  | ? {$_.ObjectType -eq "User"}