I read about a Japanese pizza with corn and mayo. Sounds interesting! I'd like to order from a place that is popular in Japan, but that's NOT considered fancy, artisan, or gourmet. From which restaurants can I order, preferably by delivery, in either Tokyo or Kyoto? Which toppings are traditionally ordered along with the corn and mayo?
I have been living in Japan for more than an year now. While I agree with the suggestion by @joe to try "Saizeriya", where you can get a decent pizza for a budget-friendly price, I would like to suggest another option that satisfy your needs.
Japan has a variety of Pizza flavors and there are food chains that offer almost all of them at a reasonable price like 'Dominos'. They have the app (English and Japanese) for both Andriod, iOS and Website where delivery is possible to almost any location in Tokyo and Kyoto. You can also custom make your own pizza in the app/website, which would be useful if you are vegetarian. The other suggested flavors to look for are Jaga-Mayo(Potato-Mayo) on Dominos menu. The prices are decent than many other pizza chains and download/use the Dominos coupon app for huge discounts available all year.
You could try Saizeriya. It is basically a budget chain of Italian restaurants. You can find many of them in central Tokyo.