I live an hour or so away, so I visit frequently and I've not found any knife shops worth a dang. Remember also that SA has its own "special" knife laws that are far more restrictive than the rest of TX. Check them out in this thread:
http://www.bladeforums.com/forums/showthread.php?t=360103&highlight=san+antonio+knife+laws
Well, that's a five year old thread, but really well traveled and shop worn. A good cautionary bit of advice, but take it with a grain of salt.
I grew up here. I work in construction (35 years) and I always carry a large folder/locker clipped to my belt or in a belt sheath. For those in the trades, the Buck 110 is still the standard blade, worn on the belt in full view.
No one gets stopped for having a locking blade knife. The law was written to give the police something to enforce when the same 110 was the gang bangers stabbing/cutting tool of choice and was a bit out of control in the 70s and 80s. The police could see the knives, knew they weren't being used for work or practical purposes, but couldn't do anything about it.
BTW, we also have law on the books that prohibits carrying fence wire cutters on your person if you aren't working on fences.... damn cattle rustlers!
There are still many that have fancy belt pouches that carry their large folding lockers, and like me, they go anywhere they please with them. Common sense is certainly the key here. When I did a short stint working at a bank in the early 90s managing a construction project, I always had a small lock blade in my pocket, certainly not within "legal" limits.
The law was made to keep the idiots at bay.
Go to the river, ride the tour barge at night so you can see the lights, and drink a margarita while on board. It is recently complete from its long and expensive renovation and is really pretty.
For a good food and a look at some traditional architecture, take a look at
http://www.yelp.com/biz/la-margarita-restaurant-and-oyster-bar-san-antonio
The margaritas are excellent, the food is pretty damn good, and the chips and sauce are great.
Across the walkway, is one of the oldest restaurants in San Antonio, complete with strolling mariachis, also great margarita, homemade tortillas, excellent guacamole, and a big menu of Tex Mex finished off with its own traditional bakery:
http://www.mitierracafe.com/
I would give a slight edge to La Margarita on the food, but on any given day it would be a toss up. A noisy, fun, free for all party atmosphere would definitely go to Mi Tierra.
Excellent food with some incredible fish dishes on occasion:
http://www.elmiradorrestaurant.com/
Cheap, good Tex Mex with some smattering of traditional Mexican dishes (this has been in national TV several times and is a favorite or Emeril Lagasse):
http://preview.tinyurl.com/244fp6x
Make sure you go to the Los Barrios on Blanco Rd, NOT Redland Rd.
Every one of those restaurants is a distinctly different style and taste of Mexican/Tex Mex food.
Literally a couple of miles from Los Barrios is one of the oldest gun shops in South Texas:
http://www.nagelsguns.net/Nagels_Guns/NAGELS_HOME.html
Not an elegant story by any means, but they have a large selection of knives. It doesn't look like much until you realize the knives are stuck everywhere in that wing of the store. There are probably 500- 600 knives on display on the walls, in the cabnets, and in other cases. Be aware though, there are NO bargains. You will pay full price on everything there. But you get to see and handle some knives you may not ever have seen anywhere else.
When they have closeouts, they get "right" on the price, and they also take some consignments which can lead to some possible bargains. Outside of Nagel's, there isn't much. We have the same Bass Pro Shop, Ninja knife mall stores and sporting goods stores that everyone else has.
Enjoy your visit to our fair city!
Robert