This trick is also commonly referred to as "Blind Snowboarding" because the fog effect never disappears, including while snowboarding. By voiding out far enough down towards the snowboarding track, you will spawn as if you just failed snowboarding, which is within Yeto's text trigger and therefore skips the Snowpeak Mountain portal.
You can do this on either side, but it is easier and faster on the right side. Roll to the corner shown in the video and get as close to the edge as possible without triggering the portal cutscene. Then LJA along the wall, and you will respawn next to Yeto, skipping the portal trigger. If you are slow at aiming, the keese will attack you, in which case you should slash them. If you spin attack them instead, you will move forward and likely hit the portal trigger or slip off the edge.
This trick saves around 24 seconds.
Unlike the Gamecube version, rupees spawn during blind snowboarding (95 R), which can be useful to skip rupees elsewhere. Additionally, although the fog still sticks around, you can still see pretty well, unlike in the SD versions.
Right after snowboarding, there is a big Midna trigger on the ground. This trigger can be skipped with two precise jump attacks on either side of the trigger. The jump attacks are easier on the right side.
After snowboarding, your respawn point will still be at the top of Snowpeak. We can use this to save time by voiding out instead of warping back to the top of Snowpeak. Just stand at the top of the stairs and perform a boomerang LJA into the void.