Oh my goodness, such great suggestions already. Most of mine will just be echoing some mentioned.
Mexico - La Cantina is a must for us each time. Guac and chips, nachos, tacos de barbacoa are all great choices.
Norway - I love the school bread!
China - I don't care for their egg rolls at all. I'd go with the pot stickers.
Germany - apple strudel with vanilla sauce or a big pretzel (never tried the nudel gratin, but it sounds great!)
Italy - arancini or gelato
Japan - My son and I always eat here and love the outdoor garden area seating at the Katsura Grill. We love their teriyaki or udon dishes.
Morocco - This is another must eat area for us. We love the Tangierine Cafe. I love the shawarma chicken platter!!
France - Okay - just about everything at Les Halles! Although, I didn't care for the macarons. Any of the sandwiches, quiches, pastries. Seriously hard to go wrong. Go with what looks good to you that day! I also have to mention that the grey goose slushies are amazing (at an outdoor stand).
U.K. - The fish and chips are a MUST! Love, love, love.
Canada - Not sure. I didn't realize food was available here, other than the sit down restaurant (which I still need to try!).