I also thought Tokyo was amazingly clean for a city (as far as cities go I suppose), and that it did indeed seem as if every day was a field trip for some school or other - and not just in Tokyo but everywhere else I went.
As far as strange looks from others ... I got them from EVERYone - Japanese, Europeans, school kids, etc. : you name it. But I did not feel as if any of them were unkind or such - more of a lazily curious "Oh? Who's this?"
As far as Asians being able to tell one another apart ... I saw and heard various different cases on this one. Some people told me it was extremely easy for them, others that it was not so easy. Language, of course, seemed to be the main factor!

As regards Burger Kings in particular, I can honestly say that I did not see a single one in Japan. But I did see PILES of McDonald's ... everywhere. So much so that it was surreal.
The traditional food of Japan is generally very carefully prepared, and I was told that sushi chefs and the like have to get special licenses to practice their trade. The Japanese in general are much more cleanliness-conscious and "purity" conscious when it comes to food and personal hygiene imo - I would be much more afraid of food poisoning here in the USA than in Japan. When I was there I was very fortunate to have my host family take care of all the cooking for me, so I ate Japanese cuisine pretty much every meal. That was not a problem for me though, as I love it and was even raised eating some of these foods to begin with. Except natto ... that is just plain nasty. I have never been able to get past the smell of it.