Is asking an author I'm reviewing to cite me a conflict of interest? I'm reviewing a paper whose work is quite related to some of my early PhD work, that was about 2 years ago. I have a paper published in a Journal that proved that method A had good solutions for the problem X.

Now I'm asked to review a paper that does a variation on method A, although they never cite my paper at all, is not exactly the same, but I think there should be a reference, if not because it is my paper, but because by the time I did the survey no one else had used that method.

Now, that said, is it a breach of interest to ask the authors to cite my work, or at least read it?
If I were you, I would ask myself the following question:  


  is it better for the paper to be aware of my work?


I believe this is the main question you need to ask. If you see your work is relevant to the problem and can enhance the paper content, then you have to point to it. If you see your work as a complement of the paper just reference it in the review.