Heavy Rider (300lb+) - Please recommend a 26" tyre to avoid tyre pinch
As a heavy rider personally, I don't have many issues with flats. 

A normal tire on the high/maximum pressure works fine to avoid pinch flats. 

The key is to check tire pressure every time you get on the bike. Even a day will allow a tire to soften 10 psi, and that will allow flats to occur. 

Road hazard flats are not avoidable except by avoiding the hazard in the first place. :)

Edit: to be clear, my answer is that it is most likely that your existing tires are not fully inflated, rather than that a different tire is needed.