If using sushi mat, cover completely with plastic wrap.
Prepare a small bowl of warm water.
Lay seaweed sheet on mat, dip hands in water and start spreading about 2-3 spoonfuls of rice onto sheet. Wet hands as needed to prevent rice from sticking. Cover all but 1 inch strip from the bottom. Sprinkle with sesame seeds if using.
Flip over seaweed and layer with fillings and roll up tightly using mat.
Slice with a sharp knife into 8 pieces. Dip knife in water to help prevent sticking.
Once all sliced, cover roll with mat and squeeze tightly to reform into even pieces.