Heat a cast iron or heavy skillet over medium high heat until fully hot.
Slice and lightly score the king oyster mushrooms. Season the beef short rib lightly with salt.
Add a small amount of neutral oil to the pan if needed. Sear the beef in a single layer until deeply browned, then flip and brown the other side. Remove and set aside.
Add the mushrooms to the same pan and press them down firmly so they make full contact with the surface. Cook without moving until well browned, then flip and cook until tender and caramelized.
While the mushrooms cook, make the sauce. In a small pot, combine Satsuma juice, soy sauce, rice wine vinegar, sambal, ginger powder, garlic powder, and dried scallion. Bring to a gentle simmer.
Stir together cornstarch and water, then add the slurry to the simmering sauce a little at a time until thick and glossy.
Return the beef to the pan with the mushrooms. Lower the heat, pour in the sauce, and toss quickly until everything is evenly coated and sticky.
Let the sauce bubble for 30–60 seconds to tighten up, then remove from heat.
Dress the Satsuma segments with olive oil and salt. Top with chopped Marcona almonds and dried scallions.
Serve the sauced beef and mushrooms over rice and finish with the Satsuma salad on top.