Prep your veggies. In a small bowl, whisk together hoisin, water, Worcestershire, soy sauce, brown sugar, and toasted sesame oil.
In a large cast-iron skillet, heat 1 tablespoon of canola oil and add the ground beef. Season with salt and Szechuan peppercorns.
Once beef has browned, scatter cornstarch on top and stir. Cook another 2 minutes. Remove beef to a plate.
Keep the cast-iron skillet over medium-high to high heat and add 2 more tablespoons of oil. Add shishito peppers and blister, 2 minutes. Add ginger, daikon, garlic, and scallions; toss another minute. Add meat, sauce, and toss to combine. Remove from heat and let cool. Fold pastry and bake.
Garnish the finished galette with remaining daikon and sesame seeds.