People say not to fuck with them at this stage, but I always remove the seed casing. Just take a toothpick and be SUUUUuper careful, remember there's a shell and there's also a membrane wrapped around the cotyledons.
I know it doesn't speed it up much, but it can take 2-3 days for that shell casing to be ejected, whereas if you popped it off it'd already be working on its nice green tan.