My (super?)caps, like these, all have ‘wide legs’ so the normal hole size will not fit them, I can change the hole size manually in Pcbnew or can I find the right footprint somewhere in the standard libraries?
Pcbnew stores copies of the library footprints in the .kicad-pcb file itself. If you hover over a footprint in Pcbnew and press [Ctrl + e] it gets loaded in the footprint editor and after editing you can directly put it back on the PCB again.
If you have multiple of these components I recommend to make a project specific library for it and put it in there, and then also update the schematic to take the footprint from your custom library.
From within the Footprint editor you can easily make a new library for your project.
I am not sure a project specific library is the right solution here. Might I suggest a personal central lib instead? See comparison on local vs central lib setup here: Project and libary setup for sharing and collaboration (Reasoning: The footprint is different from the one that comes with KiCad because the component soldered to it is different. A local lib would fit if the reason for footprint differences is specific to the project, like for example removal of certain silk screen parts that would extend outside the edge cut)
Loading a capacitor symbol directly from Pcbnew into the Footprint Editor, changing 2 pads and putting it back in Pcbnew takes about 2 minutes. Putting it in a custom library also takes a minute or 2.
Such changes are really much easier to do then trying to find something on internet somewhere, and even if you’ve found a footprint on Internet, you’ll still have to do the library thing in KiCad.
The first time you manage your custom footprints in a custom library it takes a bit of time, but after that it’s easier and you have a higher chance of succeeding compared to finding something on the 'net. (Except for really complicated footprints).
Making your own footprints is both an essential skill and fairly easy in KiCAD, so I’d advise looking at the tutorial links that @Rene_Poschl pointed you towards. For something as simple as a 2-pin capacitor footprint you would spend less time building your own footprint in your own library than the amount of time searching and verifying online footprints.
Obviously it is your choice how you would spend your time, but the small amount of effort learning how to make footprints with this simple 2-pin design will pay off big dividends later when you need a big complicated footprint that no one else has designed.
I don’t know if this helps but I created personal libraries for my components. For me the most time was spend making the directories and putting them in the “Configuration Paths”
Here’s what I ended up with:
The 3 entries at the bottom are of my libraries. Notice I did not put the 3dpackages under modules. It was always difficult to find there.
Avoid oval holes if you can. These are routed rather than drilled, an extra process before plating, so an extra cost.
9 times out of 10 a larger round hole works fine