This is fairly easy, though mostly luck-based.
After you die, you still fly for a short distance while bouncing off the ground. Coins you grab during this bouncing count towards this achievement.
Equipping either Insta-Ball or Freeze-o-Matic will extend the time you spend moving after death, so you'll have a greater chance of grabbing coins. Any coins you get after a Final Blast also count.
This should come naturally as you play, but if you want it right away, keep an eye out for a clump of coins right after a zapper, then kill yourself on it, propelling into the coins.