How to List all roles and their members (users/groups) of an Azure Analysis Services tabular model/database
this should get you started (boogles my mind that there isn't a Get-RoleMember cmdlet)

[Reflection.Assembly]::LoadWithPartialName("Microsoft.AnalysisServices")

$ServerName = "asazure://aspaaseastus2.asazure.windows.net/alignpocaas"
$DB = "alignpocaas"

$MyServer = New-Object Microsoft.AnalysisServices.Server
$MyServer.Connect($ServerName)

$myDatabase = $myServer.Databases.Item($DB)
$myDatabase.Roles