It would be "Tejano", except that term has long ago taken on a meaning different than a citizen of Tejas, to mean a "Texan of Hispanic ancestory". I like "Texican" myself, even though I'm not native born (But neither were Sam Houston,aka Big Drunk, Jim Bowie, David Crockett, or Stephen F. Austin), since it was the term used in the early days, both before, during and after the period of the Texas Republic. I don't know when it got changed to the more conventional "Texan".
It is a natural tendency I suppose that over time descriptive names become shorter. That is why I never understood why “Tejan” and “Tejans” never caught on. It is easily pronounced and fairly accurate. Tejan would be the common form and Tejano would denote Hispanic ancestry.
But of course, as it is with many things, that would be far too simple and might actually work well, therefore it will never happen.
Weird.
Might have been to separate y'all from the Texaco employees...