Seasoning is furikake or li hing mui. I have a stick of umami at home that you grate over food. Don't know what's in it.
Cut spam in 8-10 slices. Start frying.
Mix equal amounts of soy sauce and sugar. Pour over Spam as it is frying to make extra crispy. Fry to desired crispness.
Use a musubi mold to construct musubi or improvise.
On sheet of Nori, layer one scoop of rice, sprinkle of seasoning, slice of Spam, sprinkle of seasoning, scoop of rice and pack tightly into a nice rectangle the size of the Spam. Wrap Nori around and seal with some rice.