Place the potatoes in a single layer in a large wok or a wide heavy pot. Add enough cold water to cover generously. Bring to a gentle simmer over moderate heat and cook until the potatoes are tender but firm, 3 to 4 minutes. A knife inserted into the center of each potato should meet little resistance. Drain. If working in advance, plunge into ice water to chill, then drain. At this point the potatoes can be sealed and refrigerated. Bring to room temperature before proceeding.

Combine the oils.

Divide the potatoes into 2 batches. Heat a wok or large heavy skillet over high heat until a bead of water evaporates on contact. Add 2 tablespoons of the oil, swirl to glaze the pan, and reduce the heat to moderately high. When the oil is hot enough to sizzle a piece of potato on contact, add the first batch of potatoes. Toss until crispy and golden brown, 2 to 3 minutes, adjusting the heat so they brown without scorching and drizzling a bit more oil down the side of the pan, if needed to prevent sticking. Sprinkle the potatoes with half of the pepper-salt; toss to blend. Sprinkle with half of the coriander and chives, and toss to mix.

Wipe the pan clean and repeat with the remaining batch.

Serve the potatoes hot from the pan. Or, spread on a baking sheet and let cool to room temperature. When ready, rewarm in a 350°F oven until hot, about 5 minutes.