As you'll note from the article on grapes, it's the separation that causes the "spark" (or plasma as he says). Do these sparks occur only on the surface of your salsa, or do they appear to be inside too? Is this chunky salsa (e.g. fresca) by chance? If so perhaps the chunks are creating shapes in the surface that result in small gaps and produce a similar effect to the grapes. Note that I think the composition of the material matters, as in the case of the grape with a large proportion of water (and sugars?). So perhaps the salsa's composition has similarly spark/plasma-friendly characteristics...
To answer your questions, it is, of course, on the surface as you can not see into salsa. It is not transparent, nor even translucent enough to see if it is inside or not. As for the composition, it is very watery w/ sugars and is, acidic (the liquid being mostly tomato juice), so it is likely very similar composition from a pH and/or water content point of view. I have not noticed any particular brand possessing this feature, nor any particular style, so I doubt it is inherently "chunky" salsa in particular. I think it is more likely the composition --- or the "pips"
So why would you want to microwave salsa? Isn't it supposed to be served chilled, or at least only room temperature?Depends on what it's being used for - for nachos, I like personally like the salsa heated along with the chips & cheese
Agreed. Chili con Queso is a great way of eating salsa and requires it to be hot. Salsa is the ultimate snack food in my opinion. There are as many recipes as their are people who make it, it tastes good hot or cold, goes with just about anything, and is probably one of the most health snacks on the planet. What you eat WITH it may not be, but that is another issue.