This is a pretty easy one. Simply play the gather races and pick up the arrowheads. Once you've accumulated 100 across all your different races, the achievement will unlock as soon as you pick up #100.
If you've already played through every level to get the Hungry Man achievement, here's my tip for saving a few minutes and getting the last tokens faster. Play on the desert level since it's pretty short. Finish one lap collecting all 8 tokens. As soon as you've collected all 8, turn off your phone or back out of the game for at least 5 seconds. When you return to the game, all of the tokens will have respawned and you can recollect all of them. When you get to the end of the level, it will show that you collected 24 tokens instead of the usual 8.
It's not that great of a trick, but it could save you 8-10 extra laps of cro-mag rally!