During the years Wolfgang Amadeus Mozart lived in Salzburg, Austria, he made his living largely by composing piano concertos and then selling tickets to the concerts with himself at the keyboard. The San Antonio Symphony lovingly made that time as visible as possible Friday night with widely recorded New York pianist Jeremy Denk standing in for Mozart. The orchestra and Denk performed not one, but two popular Mozart concertos, Nos. 19 and 23. The concert was quite an intimate one at the Tobin Center for the Performing Arts, with smallish ensembles performing the Mozart Festival program A formal conductor was not needed. Denk conducted the concertos from the Steinway keyboard, his back to the audience. Concertmaster Eric Gratz was the “leader” from his chair for two other program pieces.