There are a few casual restaurants across from the Boardwalk, but as a local, I generally don't think of going to the boardwalk/wharf area for food. I think your "best bets" in that area are El Paisano (tamales and standard taqueria fare) and Falafel Hut. Please report back on your experience, thanks!
El Paisano Tamales
609 Beach St, Santa Cruz, CA 95060
309 Beach St, Santa Cruz, CA 95060
The Boardwalk really only has low-end carnival food. Not much to get excited about. The best bets are probably the corn dogs and garlic fries.
I've never been, but this place is across the street from the Boardwalk:
The wharf is a short walk from the Boardwalk. There are several resturants there: