With three locations in Denver and Boulder, Hapa Sushi is intent on building awareness in a fast-food universe. What better way than a virtually dick-ensian textual route? Hence we have the first of what promises to be a series of three unusual tabloid quarter pages in the Denver edition of The Onion, via Boulder agency TDA Advertising & Design. "This is paid advertising that is indistinguishable from the surrounding humorous editorial content for which The Onion is known," points out TDA CD Jonathan Schoenberg. "It is not labeled 'Advertisement.' " As for the motivation to mix food and below-the-belt humor, which would seem to be a potentially volatile combo, "People read The Onion for outrageous entertainment," he adds. "We tried to honor that."