Step by step:

my $input = 'a6.55.45.0e';;

my( $hex = $input ) =~  tr[.][]d;; ## Remove dots;;

my $revHex = reverse $hex;;

my $packedInt = pack 'h*', $revHex;;

my @tuners;;
vec( $packedInt, $_, 1 ) and push @tuners, $_ for 0 .. 31;;

print "@tuners";;
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[download]

Or as a compact sub:

sub mask2list { 
    ( my $hex = shift ) =~ tr[.][]d; 
    my $packed = pack 'h*', scalar reverse $hex; 
    map{ vec( $packed, $_, 1 )? $_ : () } 0 .. 31;
}

my @tuners = mask2list( 'a6.55.45.0e' );

print "@tuners";
1 2 3 8 10 14 16 18 20 22 25 26 29 31
[download]