Combine the cilantro, serrano and cayenne peppers, ginger and scallions in a food processor and pulse to a pesto consistency. Transfer to a mixing bowl. Stir in as much oil as necessary to give the mixture a saucy consistency, like chimichurri. Add the soy sauce, mirin, lemon juice and sugar and stir to combine. Season with salt, white pepper and more lemon juice. Store in a covered container in the refrigerator until ready to use.
This should be made fresh daily.
Recipe courtesy of Ching-He Huang