Place sliced beef in a bowl. Add ginger, soy sauce, 1 teaspoon oil and cornstarch; mix until well combined. Set aside.
Prepare the asparagus by rinsing under cold running water. Pat dry with paper towels. Trim asparagus by snapping off woody ends and then cutting into 2-inch diagonal pieces.
In a bowl, prepare sauce by whisking together water, oyster sauce, soy sauce, garlic and cornstrach. Set aside.
Heat 1 tablespoon oil in a large skillet over medium-high heat. Add asparagus and stir-fry for 2 minutes or until crisp tender. Transfer asparagus onto a plate and set aside.
Using the same pan, add remaining 1 tablespoon oil. Add beef and stir-fry for 2 minutes or until no longer pink.
Give cornstarch mixture a final stir and then add to the pan. Add asparagus and stir to coat. Cook for a minute or two or until sauce slightly thickened. Sprinkle with chopped green onions.
Remove from the heat and serve with steamed rice.