How would I rotate a character torso to the face of a brick?

When creating a CFrame using

CFrame.new(pos, lookAt)

it accepts two arguments. The first (pos) is a Vector3 position which is the location of the CFrame. The second (lookAt), is a Vector3 position which, if included, will be the position which the CFrame is facing. Thus, you can use:

lookAt = workspace.LookAtMe.Position
Torso.CFrame = CFrame.new(Torso.Position, lookAt)

The Front face of Torso will now be facing LookAtMe.

EDIT: To make the player parallel to the part, it depends on where the player is relative to the part.

If the "giant, long wall" has its Front face facing towards the player, then:

lookAt = Torso.Position - workspace.LookAtMe.CFrame.lookVector
Torso.CFrame = CFrame.new(Torso.Position, lookAt)

Alternatively, if other faces are facing the player, a different lookAt would be required:

lookAt = Torso.Position + workspace.LookAtMe.CFrame.lookVector --Back facing player
lookAt = Torso.Position - workspace.LookAtMe.CFrame.rightVector --Right side facing player
lookAt = Torso.Position + workspace.LookAtMe.CFrame.rightVector --Left side facing player
lookAt = Torso.Position - workspace.LookAtMe.CFrame.upVector --Top facing player
lookAt = Torso.Position + workspace.LookAtMe.CFrame.upVector --Bottom facing player

Using a BodyGyro might be the easiest way to accomplish what you are trying to do. You can read the wiki page here (The bottom example provides a good demonstration of how it is used): http://wiki.roblox.com/index.php?title=API:Class/BodyGyro