Thanks for your question. There are several possibilities but lacking a picture of the insects, these just will be guesses. These sites also discuss remedial procedures.

1). Here are pictures and descriptions of the most common grasshoppers and crickets in Minnesota. Given your statements about size, it seems unlikely that what you are seeing would be in this group. Nevertheless, look at them:

https://www.insectidentification.org/insects-by-type-and-region.php?thisState=Minnesota&thisType=Grasshopper or Cricket

2). Leaf hoppers are another possibility. They can be very small (1/8 inch long) up to ¼ inch long. See:

http://www.minnesotaseasons.com/Insects/leafhopper_(Agalliopsis_ancistra).html

https://entomology.umn.edu/candy-striped-leafhopper

3). Flea beetles are found in Minnesota and are very small.  They generally are dark in color.  They could make the holes in the leaves that you are observing. The holes that they make in leaves are small and clustered together. They almost look like someone shot the leaves with a shot gun. See:

https://extension.umn.edu/yard-and-garden-insects/flea-beetles

https://www.maine.gov/dacf/php/gotpests/bugs/factsheets/flea-beetles-minn.pdf

I wish that I could be more exact but lacking necessary pictures, my answer must be broad.

Good luck. If after looking at these sites, you have any questions please feel free to get back to us. Among these possibilities, flea beetles would be the most likely.