I like the restaurant on the top floor of Nordstrom. It’s in the Westfield Center, and there’s lots of tables for two that solo diners use. If you snag one of the tables against the window you have a nice view – not world-class but very pleasant. And the food is quite decent with a very good wine selection.
The other really more casual place is the market bar in the Twitter building. There’s a big fancy grocery store on the ground floor next to the Twitter entrance, and if you go all the way back to the bar, you can sit at a small table or at the counter and order from any number of the food purveyors there – you said no tacos but there’s decent pizza, burgers etc. More bar food kind of stuff. A good beer and wine list as well..