Finely dice the shallot and combine with Ponzu, mustard, and olive oil for the dressing
Thinly slice leftover steak and arrange on a place
Thinly slice cucumber and place on top of steak slices
Slice and sprinkle scallions on top of steak and cucumber
Spoon dressing over steak
Season with flaky salt if desired
notes
This recipe is a perfect use for leftover steak because it plays on the tender texture of cold steak, and so doesn't require reheating the beef **(which almost always dries it out)**.
The Ponzu sauce can be store bought, but is even better if made fresh.