Data source with Employee data

Hello Experts,

I'm implementing simple extension with usage of Custom Logic.
I need to load full name of employee.

1. Is there any view / API that I can use in Custom Logic implementation to select full name having personnel number?

2. What is best way to look for available data sources? Something more efficient, than "View Browser" filtered by release status, where I can't preview content?

Thanks in advance!

Jakub