What do Outback Steakhouse, P.F. Chang’s China Bistro, and Rachael Ray all have in common? They serve seared ahi tuna! The ubiquitous “fancy” appetizer, usually accompanied by squeeze-bottled swirls of wasabi mayo and encrusted in sesame seeds, is as out as howling coyote art from the 1980s. Plus, a lot of tuna contains harmful levels of mercury.