Season the chicken lightly with kosher salt.
Combine chicken broth and soy sauce in a small bowl and set aside.
Mix cornstarch with water in another bowl until smooth.
Heat a large non-stick wok over medium-high heat and add a teaspoon of oil once hot.
Sauté the asparagus until just tender and crisp, about 3 to 4 minutes.
Add chopped garlic and fresh ginger, cooking until fragrant and lightly browned, approximately 1 minute, then remove from heat.
Turn heat to high and add another teaspoon of oil; cook half of the chicken cubes until golden brown and fully cooked, around 4 minutes per side.
Remove cooked chicken and repeat with the remaining oil and chicken.
Pour in the soy sauce mixture and bring it to a boil, letting it reduce for 1 to 1 1/2 minutes.
Whisk in lemon juice and the cornstarch slurry, stirring continuously until the sauce thickens.
Return the chicken and asparagus to the wok, toss everything to combine well, then remove from heat and serve immediately.