Serve the sauce with chicken, fish, pork, or tofu—and always some rice. Really, just put it on whatever needs a little extra "oomph," like soba noodles or roasted or steamed vegetables. It would also work as a stellar sauce for okonomiyaki.
Combine the soy sauce, tahini (or nut butter), vinegar, sesame oil, sugar, and salt in a small heatproof bowl and mix until the sugar is dissolved and tahini is well incorporated. It’s okay if it’s not completely dissolved, though.
Heat a small skillet over medium heat, add the oil, and heat until shimmering. Add the scallions, ginger, garlic, chili flakes, and crushed peppercorns. Remove from the heat and stir for 10 seconds, until the scallion is bright green and everything’s aromatic. Pour all this into the liquid seasonings and whisk until well blended. Once cool, the sauce will keep in the fridge for one or two days.