Mr.Daniel, it is possible for you and your wife to get a Chinese tourist visa in Seoul. But you need apply for it through a travel agency designated by the Consular Section of the Chinese Embassy. The list is on the web page http://kr.china-embassy.org/chn/lsqz/ls_qz/ls_qz_13/t229558.htm
it will takes about one week for visa processing. The regular visa fee is 120,000 wons per person. The service fee of travel agency is not more than 20,000 wons per passport. So the total fee is not more than 280,000 wons.