Where can I find all tables used in ManagementObjectSearcher in win32 API

You could select appropriate tables from the following list: http://msdn.microsoft.com/en-us/library/aa389273(v=vs.85).aspx

You could also get this list programmatically:

ManagementObjectSearcher wmi = new ManagementObjectSearcher
    ("SELECT * FROM meta_class WHERE __CLASS LIKE 'Win32_%'");
foreach (ManagementObject obj in wmi.Get())
    Console.WriteLine(obj["__CLASS"]);

Microsoft's WMI Code Creator is handy for this, its a utility that lists all WMI classes in a searchable fashion, it will generate VBScript code you can run immediately to see whats actually returned and you can then use it to spit out C#/VB.Net code snippets.