Hi Guys,
Prob a noob question, I’m currently moving form Maya to Houdini. I know about the spray paint tool to paint points onto a surface, but I’m looking for something more precise. I want to add/paint a single point on each click where I click on the surface, just like the spray paint tool but just one at a time. Doe this exist out of the box or do I have to now build a HDA do to this? Thanks.

TopoBuild might be what you're looking for:
https://www.sidefx.com/docs/houdini/nodes/sop/topobuild.html [www.sidefx.com]

you can use Guide Groom SOP in Plant Tool, it has both Single and Scatter mode

- if you set Segment Count to 0 then it will place just points and while Move Tool will also work on them, Relax Tool for example wouldn't

- so I'd advise to set segments to 1, which will plant short curves, but you will be able to use Move and Relax tools to refine the placement
then afterwards just keep the root points

If you just want to create points on a world ortho plane or construction plane, then a polygon 'Curve SOP' followed by an 'Add SOP' set to 'delete geometry but keep the points' is another simple option.