When guys like a girl, they sometimes are really playful with them, like gently pushing them, throwing paper at them, etc.
But also, keep in mind, that if a guy is acting that way, it doesn't necessarily mean that he likes you. See how he acts around other girls.
You're best bet is to just ask him. Because he might just be really good friends with you, or he could like you.
From the description you gave, it's too hard to tell.