use strict;
use warnings;
use Data::Dump::Streamer;

my @a_ = ({ domain => 'adomain.com',
          data => 'adata',
        },
        { domain => 'bdomain.com',
          data => 'bdata',
        });

my @b_ = ({ domain => 'adomain.com',
          otherdata => 'astuff',
        },
        { domain => 'bdomain.com',
          otherdata => 'bstuff',
        });

my @c = map {{%{$a_[$_]}, %{$b_[$_]}}} 0..$#a_;

Dump (\@c);