Slice the spam into 1/4 inch wide pieces. You should get about 8-9 pieces. Keep the spam container!
Transfer the spam to a non-stick pan over medium heat and let it brown. While it is browning, make the marinade. Whisk the soy sauce, brown sugar, and ginger in a bowl.
Flip the spam once it’s brown and pour in the marinade. Let it cook in the marinade, stirring and flipping occasionally, until the marinade has reduced and little liquid is left. Transfer to a plate and let cool.
Cut the seaweed into thirds, about 2 inch wide strips. Clean out the spam container and line it with plastic wrap. Add about 1/3 cup of rice into the container and push it down until is compact. Add a slice of spam on top and push down. Pull the plastic wrap out.
Wrap the musubi in a strip of seaweed. Continue with the remaining spam pieces. That’s it! Enjoy!