I think your chances of successfully invoking the right to asylum under the circumstances you describe are zero. To start with, I do not think there is any country where you can "easily" search asylum from- especially not if you have lived in a certain country contrary to the legal provisions and then you want to escape legal consequences by invoking asylum- that does not sound to credible. Conditions for asylum have become much stricter in Europe in view of the many asylum seekers that came. Colombians will not be likely to be among the people granted asylum. Asylum is for political refugees who are personally persecuted. That your life is in danger because of an overall dangerous situation, or because of acts of private persons, will not be sufficient.
Then, asylum is considered a last resort, so if you have a US passport, which reason should the Spaniards have to give you asylum? You could safely return to the US. Asylum is for people who have no other choice. Even if you do not tell them, there would be ways to find out, and your denying to have a US passport could be a serious criminal offense.