How safe in Kunming, I travel single although I am also a Chinese from North America

It is ganerally a nice city with good public security. You have no need to worry much about it. However, you'd better do not go outside at late night alone.

Chinese from North America? I thought Chinese were from China and Americans were from America. Since China doesn't allow dual nationality, ou can't be both. You're probably just Canadian or United Statian. You don't hear white people there mentioning everytime which part of Europe their originate from.

As for safety, it is quite safe. But be careful with traffic, even when walking. Traffic laws aren't the same as most European countries. Make sure you carefully take your time to understand and get used to them.
As Glora said, don't venture alone outside late at night. There aren't many people out after 11pm, so you never know what kind of people you can meet during these times.
Also, Chinese people aren't confrontational, so physical fights are considerably less frequent than in European countries or countries colonised by Europeans (Australia, Canada, New Zealand, South America, USA), unless of course you provoke one after a drunken night at the expat bar.