Nobody, except Link Nukem, can learn it due to the fact he's the only protagonist in the series to carry a sword. While performing this move, Link Nukem leaps and slashes the enemy in mid-air. In normal conditions, it would deal only slightly bigger damage than from a normal attack, but when used against heavy-armored opponents, it becomes deadly. Iron Knuckles that attacked The King and Link were easily slain thanks to that move.
According to The Enclosed Instruction Book, the Armor Breaker is one of only two ways to defeat Iron Knuckle, the second being the Power Glove. Of course, even Iron Knuckle's armor has its limits and extremely powerful attacks can still kill him without the help of the Power Glove or the Armor Breaker skill.
Ganon's minion, Militron, who also wields a sword, knows the Armor Breaker skill, although the skill's name is actually "Shield Breaker", this skill allows him to shatter Bowser's force field in CD-i Pokemon Tournament.