Using primer or not doesn't have anything to do with what you're spraying as a topcoat or what method. It's all in the preparation for the actual finish/paint. If you're painting a cabinet, spraying the actual paint is probably 5% or less of the actual work. There's a lot of prep work, which is very similar, if not exactly like bodywork and prep for a car paint job.
Yes, you'll need to primer, then I'd recommend doing a light sanding of the primer coat, because you'll find more flaws that need to be filled and fixed. The eventual final primer coat..then either sanding with a very fine grit (in between coats type) or scuff with a grey 3M scuff pad, then wipe the whole thing with naptha before spraying paint (to get it clean, remove skin oils, prevent fisheyes), then..blow of with compressed air, and wipe with a tack rag. All the little flaws, dust, scratches will show in the finish, and will likely be highlighted, not hidden.
If you're spraying the finish coat, you have the option of spraying primer instead of rattlecans of automotive primer.
Just my opinion here, but I don't think there's anywhere in this hobby where flat black is appropriate.