delete on a Tie::File array leaves the newline in order to behave as closly as possible to a real array. You want to use splice:

use Tie::File;

my $file = "file.csv";

tie my @lines, Tie::File, $file
  or die "can't update $file: $!";

splice(@lines, 1, 1);
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Update: I assumed you meant "first line pass the header" or something like that. If you truly want to delete the first line, you can use:

splice(@lines, 0, 1);
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or

shift(@lines);
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