How do I become friends with this guy at work?

about 2 months ago, i spent a week at a company to decide if i wanted to intern there. i sat next to a guy and observed what he was doing. he taught me some stuff and so did the boss there for training. so i also sat by the boss. i thought this guy was really nice and like someone i'd want to become friends with. plus he's kinda cute. he just seems like he has an awesome personality. i went to lunch with the team i was working with and that guy was there too since he's on the team. so now 2 months later, i'm back at this company because i decided i want to intern there. this time i'm working for another person. so i don't get to sit by this guy. i see him around though during lunch and when i'm walking around. how do i let him know that i want to become friends? like would it be weird to ask him to go to lunch with me? i don't want him to think i want to date him. i just want to be friendly first and see where it goes. i barely know him. so i'm not sure what to do.