Do you mean the official documentation, or 3rd party examples and tutorials? Andrey has been working hard at translating the official docs to English the past few months: http://restas.lisper.ru/en/

As for tutorials, you are right that there could be more. Between https://github.com/archimag/rulisp and https://github.com/archimag/cliki2 there are some good example sites built in RESTAS.