There are many ways to map database field names to class names, but what is the simplest way to just remove the underscores?
public IEnumerable
Dapper.DefaultTypeMap.MatchNamesWithUnderscores = true;
job done ;p
The readme doesn't show any support for renaming columns. You could alias them in select:
select
select person_id as personid, full_name as fullname from fn_get_person();
as suggested in this answer.