Place the steak in the freezer for 15 minutes (this will make it easier to cut).
In a small bowl stir together the ginger, mustard, red pepper flakes, garlic, honey, black pepper, and 1 tablespoon soy sauce.
Remove the steak from the freezer, thinly slice against the grain then sprinkle on all sides with salt.
Place the cornstarch in a small bowl.
Stir together the beer and remaining soy sauce in a separate bowl.
Heat the sesame oil in a wok or skillet over medium high heat.
A few at a time, add the beef strips to the cornstarch, then add to the soy/beer mixture, then add to the skillet. Repeat for all beef.
Once the beef has started to brown, add the honey mixture as well as any of the beer mixture that may remain from the steak dredge, to the skillet.
Lower heat to medium, cooking until sauce has thickened.
Add to a serving platter, sprinkle with sesame seeds and green onions. Serve with rice.