“How are you?” is “Как делишки?” (“Kak delishki?”) in Russian if it’s an informal phrase (slang). You can use it with your friends and buddies. But basically, schoolchildren and teenagers only use it. An adult can say it to his friends or children to show that he is on friendly terms with them. Also “How are you?” can be translated like “Как оно?” (“Kak ano?”). It’s slang. But this phrase is becoming old-fashioned.