Happens to me when I start my tomato seeds every year. Good thing is it's not a full helmet head or a strangler. Just the seed coat pinching the cotyledons together. First try to just gently grip and wiggle it off. If that doesn't work then the best thing I and many other tomato breeders I know have found is saliva. Just wet your fingers and wipe the seed coat a bit. Then try to gently pinch the split seed coat and wiggle a bit to remove. If you feel the need to hold the seedling steady just use the pinched cotyledon themselves to hold onto. Take care to not damage or pinch the true leaves or stem though. Don't be overly aggressive with it as a seedling this size has a small root structure and you shouldn't be upsetting that.
Now I'm not going to claim what's best if that fails. But I personally just snip the cotyledons at this point if the seed coat won't remove easily enough. Once the seedling is up with a strong stem and the first true leaves starting to form then the cotyledons aren't vital for much longer. Given the size of that one true leave in the picture then it should be more than fine to do so. In the future you should remove the seed coat far sooner if you encounter this issue again. Having one true leaf that size and not a another right across from it to match is alarming and may set the plant back if not monitored and corrected quickly. Right now you might find the other true leaf still curled or forming abnormally between the cotyledon. You are currently holding back the apex or growing tip, other than that it is looking strong and healthy. In the future sowing the seed just a fraction of an inch deeper and packing the media better will provide something for the seed coat to grab onto and get pulled free easier.
Anyway, sorry for the long winded reply. Not an experienced hemp farmer so maybe others have better guidance. But I do start thousands of tomato seeds every year. Have gotten good at spotting these over the years. Not a huge issue for me with common varieties and I just let the seedling die. But when you've got a new variety you're perfecting, a segregating line, a few seeds from a mutation, or down to just a few 30 year old seeds then you learn how to save them from a stuck seed coat or helmet head. Good luck with this little guy and look forward to seeing how it turns out for you and how you like the tangie'matic.
Saison