The Flash isn't usually depicted as Hispanic in the mainstream comic versions. However, there might be alternate universes or specific story arcs where his ethnicity is presented differently.
Well, the origin of Flash varies depending on the comic version. Sometimes it's a lab experiment gone wrong, and other times it's a mysterious force that grants him super-speed. But in most cases, it's a sudden and unexpected event that transforms him.
Most web comics nowadays aren't made with Flash. Artists have a wide range of options like specialized comic drawing software or even hand-drawn and digitized methods. Flash has become less popular due to its limitations and the availability of more advanced tools.