Slice the flank steak into thin strips, cutting against the grain. Place the sliced beef in a Ziploc bag with cornstarch and shake until well-coated.

Heat a large skillet over medium-high heat and add olive oil. Once hot, add the coated beef in a single layer and cook for 3-4 minutes on each side until browned.

In a medium bowl, whisk together soy sauce, water, brown sugar, rice vinegar, sesame oil, fresh ginger, garlic, honey, and a splash of cornstarch until smooth.

Reduce heat to medium, pour in the teriyaki sauce, and simmer for 2-3 minutes until it thickens slightly.

Return the seared beef to the skillet, tossing to coat with the sauce and cook for an additional 1-2 minutes.

Remove from heat, serve over rice or noodles, and garnish with sesame seeds and green onions.