This is really just the same thing as you do, but much briefer and IMHO a lot easier on the eyes:

sub option {
    my ($self, $key, $value) = @_;
    return defined $value ?
        $self->{options}->{$key} = $value :
        $self->{options}->{$key};
}
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Merging hashes (or an array into a hash, which really is the same thing) unfortunately really is cumbersome in Perl since there's no built in way to do it. The %hash = (%hash, @array); method is agreeable, readability wise, but pretty inefficient - only use it in seldom used code and/or small sets of data. My solution:

@hash{ map $array[$_], grep !($_ & 1), 0 .. $#array } = map $array[$_]
+, grep $_ & 1, 0 .. $#array;
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The greps get a list of the array's indices and filter out the odd and the even ones, respectively, then the maps turn the index lists into values out of the array. The odd-index values set up a hash slice, the even-index values feed it. Of course this painful on both eyes and fingers. I would make a sub that I can safely stash it away:

sub merge_hash {
    my ($hash, $array) = @_;
    @$hash{ map $array->[$_], grep !($_ & 1), 0 .. $#{$array} } = map 
+$array->[$_], grep $_ & 1, 0 .. $#{$array};
}
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This way I can just write down merge_hash(\%hash, \@array); and get an efficient and descriptive piece of code. You may even want to make it

sub merge_hash (\%\@) {
## rest unchanged
}
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so that you can simply write merge_hash(%hash, @array);. But beware, Perl will then insist on seeing a % and a @ even if you're passing a hash and an array reference - just like with the first parameter of push for example.