If you were the richest man in the world, where would you eat lunch while in Washington? According to a Yeas & Nays source, Mexican billionaire Carlos Slim Helu decided on Dupont’s seafood restaurant Grillfish on Tuesday afternoon. We’re told he was joined by a group of four men and spoke with another customer about the nude mural, a fixture at the restaurant since its opening 15 years ago. Helu ordered the Mediterranean bass and ate everything … except the skeleton.