Even after working with Kentico for years you can spend a lots of time on a feature request from one of your clients to find out Kentico supports it out of the box. Today I got a last minute request for a new website. "Can the home page be reached using domain.com instead of domain.com/home.html".
After experimenting a bit with the homepage "Document aliases", "Document URL path" and the "Default alias path" of the site itself i found a small setting doing exactly what I needed.
Under Settings > URLs and SEO > SEO - URLs you can find the setting Default page. With the option "Use domain root".
Hope this saves you some time.