ls -Recurse -ErrorAction SilentlyContinue | sort -Property Size | select -First 10

void Main()
{
    GetFilesSize(@"C:").OrderByDescending(x => x).Take(10).ToList();
}

public IEnumerable<long> GetFilesSize(string directory)
{
    var accessDenied = false;
    var dirList = new string[0];
    try
    {
        dirList = Directory.GetDirectories(directory);
    }
    catch{
        accessDenied = true;
    }

    if(accessDenied) yield break;

    foreach (var dir in dirList)
    {
        foreach (var size in GetFilesSize(dir))
        {
            yield return size;
        }
    }

    foreach (var fileName in Directory.GetFiles(directory))
    {
        if(fileName.Length>=260) continue;
        yield return new FileInfo(fileName).Length;
    }
}

PS C:Windowssystem32> $x=Get-ChildItem ./
PS C:Windowssystem32> $x.GetType()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     True     Object[]                                 System.Array

PS C:Windowssystem32> $x[1].GetType()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     True     DirectoryInfo                            System.IO.FileSystemInfo

PS C:Windowssystem32>