Basically, you are calling an external command, so Windows has to load up cmd.exe (dir is an inbuild command in cmd.exe as far as i know). You could very easy accomplish what you are trying to do within Perl. Doing it within perl also makes it way more portable.

If you only want the directory listing, you probably just can use glob:

#!/usr/bin/perl
use strict;
use warnings;

my $files = [glob('*')];
print "@{$files}\n";
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To learn more about glob, typing perldoc -f glob should work. If not, then your ActivePerl*\bin directory is not in your PATH. From memory: Right-clicking on Computer, Properties, Extras, Advanced and then System Variables should let you edit the PATH variables. You'll have to restart open cmd.exe windows (no windows reboot required).

Want more info about the files, like say file sizes to the file name? You could use hashes to store the data and stat to get the information. Here's a simple example:

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

my @filenames = glob('*');
my %files;
foreach my $fname (@filenames) {
    my $size = (stat($fname))[7];
    $files{$fname} = $size;
}

print Dumper(\%files);
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For more complicated things like recursive directory traversing you should take a look at CPAN modules like File::Util and/or File::Find.

But in general, i endorse people new to Perl to at least once code their own recursive finder. It's a nice learning experience and nearly everyone on PerlMonks can help you out if you get stuck.