The SKS has a 20inch barrel. The front sight removal appears to be straight forward on the Chinese / Russian SKS. I found these instructions online for you.
Remove the stock, put the SKS into a padded gun vise. Ensure that the front sights are accessible.
Drive out the two rear pins securing the bayonet lug with a punch and hammer. One pin is solid and located in the bayonet lug that protrudes from the bottom part of the barrel. The other pin is a hollow roll-pin located in the sight base that protrudes from the top of the barrel.
Heat the sight and lug with a propane torch for one minute to help expand and loosen the metal.
Place an aluminum block against the front sight and bayonet lug. Use a shop-press or gear puller to push the block towards the muzzle until the sight is pushed off the barrel.
good luck