Do you use sprinklers for irrigation?
Water droplets can made this holes on sunny days.
Nope. I'm currently watering this remote garden with a bucket (luckily, it's next to a pond).I haven't found anything on the underside of the leaves. In researching this, flea beetles seem to fit the description, except they aren't bothering my tomato or pepper plants. Same thing last year. Whatever it is, it only attacks the tomatillos.