In Chicago, “Canning” and power go together as surely as hot dogs and mustard. Not only does he oversee the largest private equity firm in the city, but he’s got his finger in a zillion pies, from Exelon (he’s a director) to the Museum of Science and Industry (he’s chairman). He made an unsuccessful bid for the Cubs in 2008. If the Ricketts make good on their vow to sell a 20 percent stake in the team, could Canning be the one to gobble it up?