Get list of SSAS server admins
Solution 1:
You can run an XMLA query against your SSAS instance as follows:
DISCOVER_XML_METADATA
<Discover xmlns="urn:schemas-microsoft-com:xml-analysis">
<RequestType>DISCOVER_XML_METADATA</RequestType>
<Restrictions>
<RestrictionList xmlns="urn:schemas-microsoft-com:xml-analysis">
<RoleID>Administrators</RoleID>
<ObjectExpansion>ExpandObject</ObjectExpansion>
</RestrictionList>
</Restrictions>
<Properties>
</Properties>
</Discover>
Sample output in my machine: