Heat up a skillet, add the oil, pan-fry the sliced spam on medium heat until both sides are slightly brow in color. Remove from the skillet, drain the excess oil on a plate lined with paper towels.
Keep a bowl of water next to you. On a flat surface, line a sheet of plastic wrap, then add a sheet of cut nori seaweed (2 to 3 inches/5 cm-7 cm wide). Place the musubi mold in the center of the seaweed.
Wet both hands and arrange each portion of the rice into the musubi maker. Make sure all the corners are filled with rice.
Press down the rice using the presser of the musubi maker. Make sure the rice is tightly packed. While pressing down, carefully remove the rectangle mold from the rice.
Brush some teriyaki sauce on top of the rice.
Place a piece of spam on top of the rice.
Pull both sides of the seaweed up and seal tightly. To seal the seaweed, use a few grains of rice on one end of the nori. The sticky rice will help the nori stick together. Repeat the same process until all the ingredients are used up.