PYONGYANG, North Korea — Street stalls that offer North Koreans a place to spend — or make — money on everything from snow cones to DVDs are flourishing in Pyongyang and other North Korean cities, modest but growing forms of private commerce in a country where capitalism is officially anathema. In sharp contrast to the common but semi-clandestine activities of old women hawking loose cigarettes on city backstreets or farmers selling their produce in makeshift fruit stands along highways, the kiosks appear to have the support of some important backers and are both conspicuous and spreading fast. Near Pyongyang's main train station, for example, a hamburger stand is doing good business.