Most breakable walls in this game can only be destroyed from one side but it is possible to break them from the wrong side by using certain skills.
Sentry
If you stick at the top of the wall and use Sentry, it will move at a position where it can deals damage to the wall. Repeat it enough time and you will break the wall.
Shuriken
If you stick to the wall and use shuriken, some of them will pass through the wall and start damaging it. Repeat it a couple times and you will break the wall.
Hammer
If you stick to the upper part of a wall and use hammer you will be able to break small walls. This only works on the small walls and not on the bigger barriers. You can hit the walls more consistently if you combine it with slowdown.
Spear
If you stick to the upper part of a wall and use spear you will be able to break small walls. This only works on the small walls and not on the bigger barriers.