Publishing with a Pseudonym that uses my legal first name as last name
I would not use your first name as a last name.  Especially in the West, a surname is a kind of "strong" identifier, and using one in publications that doesn't match what you use on a daily basis-- or worse, that matches the wrong daily name-- could lead to many strange situations.  People may address you incorrectly (Dr. First Name instead of Dr. Surname), enter your data in systems incorrectly (I've dealt with this personally many times, and it is universally hard to get databases updated), and so on.

You should also consider that it's relatively rare to look up an author only by their last name these days.  Once you build up a career in your field, people will remember you by your first and last names, or by your surname in combination with your co-authors.  I've also seen many people of Asian descent use both their English and Asian names in their publications (like, e.g., Xiaoye Sherry Li), which leads to a unique and searchable name overall.

If you really just want to get rid of your legal surname, you can look into changing it. 
 This, of course, depends on laws and bureaucracy, but for people who are really disturbed by their names, it can bring life-long relief.