Trim bottoms off Chinese broccoli. Trim leaves and reserve. Slice stems into 2" pieces at an angle. Trim green onions and cut into 2" lengths. Slice 3 or 4 green portions of green onions into very thin rounds. Thinly slice garlic. Slice four thin rounds from Fresno chile. Remove seeds, ribs, and mince remaining chile. Pat salmon fillets dry, and season flesh side with ¼ tsp. salt and a pinch of pepper.
Sear the Salmon
Whisk together ponzu, ginger, minced Fresno (to taste), 1 Tbsp. olive oil in a mixing bowl. Place a large non-stick pan over medium-high heat and add 2 tsp. olive oil. Add salmon to hot pan, flesh side down, and cook undisturbed until browned, 2-3 minutes. Transfer to prepared baking sheet, flesh side up. Reserve pan; no need to wipe clean.
Start the Vegetables
Return pan used to sear salmon to medium-high and add 2 tsp. olive oil. Add Chinse broccoli stems to hot pan and stir occasionally until lightly charred, 3-5 minutes. Add Chinese broccoli leaves and green onions and stir occasionally until green onions are lightly charred and leaves are wilted, 3-5 minutes. Leave vegetables in pan; they will continue cooking in a later step. While vegetables cook, finish salmon.
Finish the Salmon
Place baking sheet in oven and bake until salmon reaches a minimum internal temperature of 145 degrees, 5-7 minutes. While salmon roasts, finish vegetables.
Finish the Dish
Add garlic, Fresno chile rounds (to taste), ¼ cup water, ½ tsp. salt, and a pinch of pepper to pan with vegetables and stir occasionally until garlic is tender and water is evaporated, 2-3 minutes. Place vegetables on a plate. Place salmon next to vegetables and drizzle sauce over salmon. Garnish with green onion rounds.