I want to seek some ideas about what kind of topics I can talk about during the dinner or lunch time during my upcoming on-site faculty interview. I will have a dinner with the searching committee, department head, and other faculty members in the department. What typical topics I can pick up to avoid silencing the time.
Actually, this advice is quite different from that of Wetenschaap, though I don't disagree with that suggestion.
Instead of talking about yourself, spend the time asking about them. Ask about the students. How motivated are they? Ask whether there are unique aspects of the educational program. Ask about their future goals. Ask about trends, both positive and disturbing that they see on the horizon. Ask about collaboration. Ask about the research of others. Ask about what research seminars are available.
And these are things you want to know before accepting an offer.
Or ask about the local environment. Are there good places to, say, ride a bike or hike. If you have a partner, ask about opportunities for them locally.
Lots of things. But don't make it too focused on yourself or you might seem narcissistic.
The more social events of an interview program are typically meant for the candidate and the other participants to get to know each other better. They would like to know: who are you as a person, beyond your direct research and teaching interests? Do you have any hobbies? Do you play any sports, or instruments? What are your favorite travel destinations? Depending on your personal interests, you can keep topics closer to your research field, or further away into general knowledge / state of the world things. Make sure they get an authentic impression of who you are, what makes you tick, how you reason about things.
If the other faculty members and the department head have not been part of the formal interviewing process so far, you can inquire after their own research interests, and try to make connections with your own work. Building bridges cannot hurt.