Just got back from a few days in S.A. Thanks to all the Chowhounders who turned what would otherwise have been a dismal and expensive trip into a wonderful foodie experience.
By far the best place we tried was La Fogata. It is about a $15 taxi ride from the Riverwalk, but my group of four saved more on the food than the round trip cab. Great marguaritas, guacomole prepared at the table, everything there was delicious. For $10 the mariachi band will play a love song at your table. This place is not to be missed.
My hotel was along the Riverwalk. Draft beer is $5.50 on the Riverwalk, and everything else is comparably priced. Fortunately, it was only a couple of blocks to Schilo's Deli. Great wurst & hot german potato salad. Very reasonable prices, friendly service. Full of locals for lunch.
El Mirador was also terrific for lunch. They have daily specials which are very popular. Unfortunately, the corn soup had run out before we arrived. Another place I would be happy to go back to. Huge portions for lunch (especially in such a hot climate). Very reasonable, and almost exclusively locals.
My only dinner on the Riverwalk was at Boudros. It was O.K., but nothing special. Sort of like they try too hard to be trendy. If I ever return to San Antonio, I will probably avoid the Riverwalk altogether for eating.