I'm planning to install 3/8 inch hardwood floors over a concrete slab. I pulled the carpet up last night to begin a moisture test. The house was built in 1993. When it was built the builders must have spray painted the walls and ceiling with a primer and it is all over the floors. More so close to the wall than in the center of the room. Does this paint need to be removed prior to gluing down the floors or will the adhesive stick as is? My guess is that it needs to be removed, if so what is the best way to remove it?

I also discovered some small cracks in the foundation. What is the best way to seal these cracks?

Any help is greatly appreciated.

It's normal. In track homes, the name of the game is blow and go. Nothing is masked off and all the crud ends up on the floors. Joint compound, glue, paint, stain, etc. Especially around the edges. If the slab is smooth enough, you can scrape the paint off with a razor scaper but this is hard work. Another option is sanding it off using a buffer. The paint and other contaminents does need to be removed. Hairline cracks will be filled with the adhesive. Larger cracks, 1/4" or more, are a cause to be concerned and a licensed professional should examine them prior to proceeding.