In most cases, you can use either one.
There is a slight distinction sometimes, but not an important one. I advise my students to use "how about" when the focus of the question is feelings. It's like an abbreviation of "how do you feel about ...?"
Q: Would you like pizza for dinner?
A: I prefer something lighter.
Q: How about salad?
Q: Is David coming for dinner?
A: He said he is busy tonight.
Q: What about Simon?