There was mention of a Salvadorean restaurant in San Pablo in Chownews a few issues back. I hadn't seen the original posting, but I made a note in case I was ever out that way. Yesterday I was.
Wow! It's the perfect Chowhound place. Wonderful cooking (mom in the kitchen - literally), incredibly friendly service, low prices. When you sit down you're given a big bowl of curtido, the Salvadorean pickled cabbage that would make you swear off coleslaw forever, and a dish (frequently re-filled) of light, totally non-greasy chips.
We ordered pupusas (a lovely version,) Salvadorean tamales, fried plantain, steamed yucca, a menudo-like dish and a number of small plates (about $1.50) whose names I can't remember. There is also a Mexican menu which we didn't try. (If your group spends $15 or more you get a ticket for a drawing for a Thanksgiving turkey - cooked by Mom, her way, the waiter explained.)
It is VERY hard to find. It's at the back of the International Marketplace (between San Pablo Avenue and I-80 - take the El Portal exit from 80 and head west a couple of miles.) It's basically in a construction site, next to a bigger restaurant called something like "Susy's Country Shack" and has only a small sign in the window.
The inside is diner-like, but airy and friendly. It was relatively full at 2 p.m. on Sunday, so someone must be able to find it - very much worth the effort! One more reason you really need Chownews.