Bring a few cups of water to a boil in a large pot with a steamer basket in place. Add the zucchini noodles to the steamer, cover and cook, stirring halfway through, until tender, about 3 minutes. Remove the steamer basket to the sink and let the noodles drain and dry out a little.
Whisk the soy sauce, oyster sauce, sherry, sugar and red pepper flakes in a medium bowl. Set aside.
Heat 1 tablespoon peanut oil in a large skillet over high heat. Add the scallion greens and stir until charred, 30 to 45 seconds. Remove to a plate.
Pat the shrimp dry and season with salt and pepper. Add 1 tablespoon peanut oil to the skillet. Add half the shrimp in a single layer and cook, turning once, until opaque and cooked through, 3 to 4 minutes. Remove to the plate with the scallions. Repeat with the remaining shrimp; remove to the plate.
Let the pan get very hot again. Add the remaining 1 tablespoon peanut oil. Add the bell peppers and jalapeño and cook, stirring, until browned, 2 minutes. Reduce the heat to medium low and stir in the garlic, ginger and scallion whites; cook 1 to 2 more minutes.
Add the sauce to the skillet and heat through. Remove from the heat and toss in the shrimp and scallion greens. Serve over the zucchini noodles.