Prepare a fryer or a large stock pot filled 1/3 full with oil heated to 375 degrees. Pat prawns dry with paper towel. Add prawns to oil and fry for about 2 minutes, until just cooked through. Remove prawns to a paper towel-lined plate. Meanwhile, in a large wok or saute pan over high heat coated lightly with oil, add onions and garlic chives and stir-fry for about 30 seconds. Add prawns and Kung Pao Sauce and stir-fry to combine. Season if necessary. In same deep-frying oil, add mung bean vermicelli. The noodles will immediately puff up; transfer to a paper towel-lined plate. To serve, set vermicelli in center of platter and top with Kung Pao prawn stir-fry.
For the Kung Pao Sauce:
In a wok or saute pan coated lightly with oil over high heat, add garlic and ginger and saute for 1 minute, just to soften. Add sambal, taking care not to inhale the chile, and saute until well-blended. Add soy sauce to deglaze, then add sugar and rice vinegar. Bring to a boil and slowly whisk in slurry to thicken. Check for flavor and season if necessary. Keep warm to use in recipes or cool to room temperature, store in an air-tight jar and place in the fridge.