I’m surprised that no one has mentioned how misidentifying your race on an application can jeopardize your admission status. If you truly do not appear Asian, have an Asian last name, actively participate in the culture/community, etc., I would caution against identifying solely as Asian on your application. It sounds like would be a lie to identify only as Asian on paper while admitting that you do not identify as such in your life. I’m not sure how likely colleges are to challenge an applicant’s reported demographics, but if anyone were to check your application against your previous records, you could be accused of lying to gain an advantage over others since you have only identified as Caucasian on your previous records.
If there is an option to identify as both Asian and Caucasian, that would be acceptable, but I’m not sure if that will help you any.