There are several murals along this street in the Barrio Viejo. (You can find others in the mural map.) This one's at 555 S. Meyer.
Update (May 31, 2019): Who was the artist? The scroll of paper near the bottom of the painting is signed “Francisco / 1990”:
Little mural painted for Patricia. If you know, please leave a comment below. (You can remain anonymous.)
Update (June 20, 2019): Thenks to David Aber for tracking down the artist. It's Francisco Franklin, a Tucson artist for 50 years. He sells other artwork, too; he's represented by Jane Hamilton Fine Art. His page on her website is janehamiltonfineart.com/franklin/.