Blend the Marinade: Place the tofu on a plate or baking sheet. In a blender, combine the soy sauce, hot chile sauce, serrano chile (if desired), cilantro, garlic, and ginger. Blend until the mixture is smooth and well combined.
Marinate the Tofu: Brush each tofu slice generously on both sides with two-thirds of the prepared chile mixture, reserving the rest for serving. Cover the tofu with plastic wrap and refrigerate for at least 1 hour, or up to 6 hours for enhanced flavor.
Prepare the Tofu for Frying: Heat about ½ inch of peanut oil in a large skillet over medium-high heat. Lightly coat each tofu slice in cornstarch, ensuring both sides are evenly covered, and shake off any excess.
Cook the Tofu: Fry the tofu slices in batches in the hot oil, turning them as needed, until they are golden and crisp on both sides. This should take about 1–2 minutes per side. Once cooked, transfer the tofu to a plate lined with paper towels to drain any extra oil.
Make the Salad: In a large bowl, toss the baby kale or spinach with olive oil and a pinch of fine sea salt until evenly coated. The greens will soften slightly from the oil, which is what you want.
Assemble and Serve: Gently toss the fried tofu with the prepared salad greens. Serve the dish immediately, garnished with sliced scallions and a drizzle of the reserved chile marinade for extra flavor. Enjoy warm.