Rice: Wash rice thoroughly. Add to a saucepan with water. Bring to a boil then immediately reduce to low. Cover and simmer for 20 minutes. Turn heat off and allow to sit for another 20 minutes. Dissolve 1/4 cup sugar in 1/2 cup rice vinegar over low heat. Mix with rice along with a pinch of salt. Place the seasoned rice on a small rimmed baking sheet evenly, cover with plastic wrap, and refrigerate overnight (or for at least 4 hours).
Korean BBQ Sauce: Add gochujang, ketchup, 1/4 cup rice vinegar, brown sugar, grated garlic, and grated ginger to a pan over low heat. Allow to thicken. You can place the spam into the BBQ sauce to warm up as it's reducing, or sear the spam separately and brush the sauce on afterward.
Crispy Rice: Cut the chilled rice into desired musubi-sized portions. Fry the rice in 350F oil for around 45 seconds to 1 minute per side, just to crisp the outside while leaving a soft center. This step is optional.
Assembly: Lay down a nori sheet, followed by a piece of crispy rice, then a slice of spam. Wrap the nori around, using more of the Korean BBQ sauce to seal the ends together. You can cut these in half for a smaller appetizer.
