Get a cruddy wood chisel you do not care about wrecking and pop the spots off.

It may damage the paint, but not always.

Yes, use an old chisel or, better yet, try a trowel or long handled paint scraper--anything to scape off the dried concrete. Even a screw driver might work. Good luck!

The sharper the tool the less chance of damaging the surface if handled carefully.

A 'crank neck' chisel would be the perfect tool, but they are expensive.

There is no way I would risk the damage to my 9 inch long 3/4 inch wide crank neck.

Traditional Woodworker has them, but they start around $50 for a 3/4 inch.

Smaller would be much harder to use without damage.

Here is a link that might be useful: Crank Neck Chisels