Make the sauce: Mince garlic, and add all sauce ingredients to a small bowl. Stir to combine and set aside.
Halve or quarter the mushrooms (wiped clean). Cut asparagus into 1-inch pieces, woody ends removed. Slice green onions.
In a large skillet (or wok) over medium-high heat, add sesame oil.
When hot, carefully add the mushrooms and cook for 3-4 minutes.
Add the asparagus and green onions. Cook another 3-4 minutes, stirring often.
Re-stir the sauce, then add to skillet. Stir well and cook for 2-3 minutes (or until vegetables are desired tenderness).
Garnish with sesame seeds and spoon any remaining sauce over the vegetables before serving if desired.
