In a small bowl whisk together the soy sauce, chili paste, fish sauce, and sugar. Set aside until ready to use.
Heat a large cast iron pan or wok over medium heat, add oil and heat. Add potatoes and fry until browned all over, about 6 minutes. Remove to a large bowl.
Return the pan to medium heat, add the cauliflower and cook, stirring occasionally, until just softened, about 6 minutes. Remove to the bowl with the potatoes.
Return the pan to medium-high heat and add the onion, bell pepper and celery, cooking until the onion is soft, about 4 minutes.
Next, add the garlic, ginger, peppercorns and chiles, cooking until fragrant, about 10 seconds.
Return the cauliflower and potatoes to the pan. Add the sauce and half the peanuts to the pan and toss to coat. Continue to cook until it reduces and forms a sticky glaze.
Remove from heat and serve the Kung Pao cauliflower immediately topped with the remaining peanuts, jalapeños and green onions.