Toss beef (1 Lb) in the freezer for 10 to 15 minutes before cutting, then slice against the grain as thinly as possible.
In a large bowl, whisk together sherry (2 tablespoons), soy sauce (1 tablespoon), cornstarch (1 tablespoon), salt (a pinch) and pepper to taste.
Add sliced beef to the bowl, and toss to coat in the marinade. Set aside for 15 minutes.
Heat cooking oil (1 3/4 cups) in the wok until oil begins to shimmer.
Add the beef and stir gently so it doesn't stick together. Cook for about 2-3 minutes.
Transfer the meat to a plate heavily lined with paper towels. Dab off access oil.
Pour most of the oil out of the wok, leaving about 1/2 tablespoon worth.
Turn heat in the pan to high, allowing it to smoke slightly.
Add minced garlic (3 cloves), minced ginger (1 tablespoon), crushed and minced Thai peppers (2) , soy sauce (1 tablespoon) and sesame oil (1 teaspoon) — stirring constantly until they become fragrant (about 30 seconds).
Add the beef and mix everything together.
Remove from heat, and serve beef over veggies and rice. Sprinkled with sliced green onions and sesame seeds. Enjoy!