Snowpeak Piece of Heart Locations
There's only a single piece of heart for you to obtain in Snowpeak and it's acquired by beating Yeto and Yeta in races. You will not be able to participate in this mini game until you beat the Snowpeak Ruins - after you do just port up to the top of Snowpeak and speak with Yeto and Yeta (shown in my screen shot below) to start the mini game.
Yeto is extremely slow and is the first person you'll race. You won't need to take any short cuts to beat him and you'll barely even have to 'speed up' while racing him. Yeta on the other hand is a much more difficult opponent than Yeto. For her you'll need to take every short cut and be racing at full speed almost the entire time.
Once you defeat both of them, you'll be rewarded with the piece of heart you're after. That's all there is to it!