It may not be real sushi...
...but it sure as hell is good.
Paradise Island, AKA half an avocado topped with diced tuna, salmon, and yellowtail. Topped with tobiko and scallions.
I'm actually not that big a fan of tobiko, but raw fish is rapidly growing on me these days. Especially tuna and salmon. The texture of yellowtail actually doesn't quite suit me, so whenever I have this I generally order it without.
Unsurprisingly, in Japan they don't put shrimp tempura or avocado or any of the other American sushi goodies in their rolls. However, genuine sushi makes up for it by having fresher fish straight from the Pacific.
Additionally, fresh/genuine sushi can be obtained in Chicago. There's a restaurant downtown where the chef chops up the fresh fish in front of you. The price is fair (~$100 for two people) for what you get.