Completing an expert puzzle in five minutes or less difficult? Nah, not really. At least in this game that is.
In MS Mahjong the H-key on your keyboard is your biggest friend. When you press it you get a hint on a possible match of stones.
To get this achievement keep your left index finger above the H-key and keep your right hand ready to abuse the left click of the mouse. Press the H-key and then left click the match that is shown. Do this for the entire puzzle. It should take somewhere close to a minute.
If at some point you have no more matches make sure to choose continue! Otherwise you'll get a new puzzle and we don't want that. Choose reshuffle and get back to clicking the H-key and the left mouse click. When the puzzle is solved you'll have gained an easy 10GS.