How to remove stucco paint from an entire wall?

Sandblasting? Even that would probably leave some paint in the wall.

This is one reason that I never paint masonry -- you can never get the paint off.

Stucco or paint, which one? Do you have actual stucco or is it heavily textured paint?

It is stucco

Real stucco is very hard and brittle. Cover your floor with a heavy tarp and the use a light sledge hammer to smash/break the surface. It is held by lath or wire mesh which will release the stucco when struck fiurmly, you can the later remove the lath or mesh. Is this interior or exterior?

Interior

Take a nail and try to drive the nail into the wall, what happens?

It is hard to drive nail into the wall.

Then it may actually be stucco which I have never seen installed on an interior. Get that 3 lbs sledge and start wacking.