might not be directly implemented yet in 2.8
here is another way to do it
You still can project 3D cursor to a surface.
You just have to use 3D Cursor from toolbar to have access to 3D Cursor orientation menu in Topbar.
Choose Geometry.
Just click on surface -> 3D cursor is placed and oriented.
Then, add an object. (There could be an option “align to 3D Cursor” like “align to view” but that means to control all “Add mesh” operators. Currently, there is none. Devs have other priorities.)
So, you have to go to Orientation menu in header of 3DView > Change it from Global to Cursor.
Then, you can go to Object menu > Transform > Align to Transform Orientation.
happy bl