You can use Google scholar and then filter by subject area. The downside is that this approach will only pick up authors/researchers that have a google scholar account.
See for example the sorted highly cited in the field of structural optimization
In the Web of Science, you can sort the results of a search by the first author's last name.
For a more detailed approach, there is a whole field called "bilbiometrics" that works with citations. One brach of biometrics is itself devoted to the definition of research fields and the location of authors within those fields.
You can use Google scholar and then filter by subject area. The downside is that this approach will only pick up authors/researchers that have a google scholar account.
See for example the sorted highly cited in the field of structural optimization
Very interesting and useful question. I believe using the 'academia' and 'Google scholar' is the best way of developing a pick of most cited authors and researchers in any given area. All the best
I have tried google scholar. It works if you search in google scholar profile. Here is an example of search for the top authors in "Digital Human Modeling" https://scholar.google.com/citations?view_op=search_authors&hl=en&mauthors=label:digital_human_modeling