“I have been living in my new home for 2 years in San Marcos, CA. My house is located on the corner in a residential neighborhood. Do I have any legal recourse with the city to remove the signs or at least present the “no parking” in a more subtle manner?”
You may be out of luck with regard to the city. The street and parking belongs to the public and is regulated by the appropriate municipality. However, there are procedures that must be followed when a city makes changes of this nature, and you could look into whether those procedures were properly followed in this instance. If they were not, then you may have the right to have the change reversed, or at least postponed.
Another thing you can check into is the local city ordinances. These may specify some limits on the city’s ability to restrict parking. (On the other hand, since you live on a corner lot, they may be required to restrict parking in order to maintain visibility for cars coming around the corner.)
Alternately, you could simply ask and see if they are willing to make any changes to the signage, even if they are not legally required to do so. It might be a long-shot, but it doesn’t hurt to ask.
Finally, you may have a claim against the people who sold your house to you, if they knew that this was going to happen and failed to tell you. Since it has been two years since you bought, that may not be the case, but if, for example, there was a public notice of the pending change, they may have known about it.