There are pros and cons to painting a floor. Vinyl flooring presents a different set of problems from wood or concrete. First, preparing the surface: Vinyl is very slick, so it is difficult for paint to adhere to it unless it is prepared. Check with your paint store and see if there is a chemical wash that will break the seal. For instance, the chemical wash TSP will de-gloss a painted surface. I know there’s a cleaner to prepare concrete for paint, but I'm not sure about vinyl.

Once it's clean and de-glossed, prime it first and then paint. Again look to your paint dealer (and read the label) for recommendations on what kind of paint to use. Personally, I'd use oil-based enamel floor paint, but there may be a new formulation (such as latex so cleanup will be minimal) that I'm not familiar with that will work as well, or better. Seal the painted surface with a clear finish (compatible with the type of paint you use). Because a floor takes the most abuse of any surface in the house, it needs some extra protection. The most important thing to remember is that whether you are going to paint or even install another flooring over the vinyl, your original floor should be in good condition.

If you decide to stencil, do it before you seal.

I really like using paint to pull a room together; however, in this case I am concerned about the paint adhering. How about trying all the steps in an inconspicuous place, just to see how it works? Use a leftover piece of the vinyl, or check with a flooring store for a discontinued sample to experiment with.