In a nonstick pan or griddle over medium-high heat add salmon and cook for about 4 minutes per side, flipping with a spatula. While the salmon is cooking, to a large cold skillet, add 2 tablespoons oil and garlic, then, turn pan on to protect garlic from burning. Add sliced mushrooms, and bok choy stalks, stirring constantly for 1 minute. Cover pan and cook for 5 minutes. Remove the lid and add the bok choy leaves, soy sauce, sesame oil, and continue to cook for another 2 to 3 minutes or until the leaves have wilted.
Pile the mushrooms and greens on a plate with the salmon. Season with salt and pepper and serve immediately.