Prep the aromatics: Finely grate the ginger and mince the garlic. Keep them small so they blend smoothly into the sauce.
Mix the base: In a small bowl, combine soy sauce, sesame oil, and rice vinegar.
Stir to blend.
Add sweetness: Whisk in the sugar until fully dissolved. Taste; it should round off the salt without making the sauce sweet.
Layer the flavor: Add ginger, garlic, sesame seeds, and scallions. Stir well so the aromatics distribute evenly.
Adjust texture and brightness: If you want a silkier finish, whisk in neutral oil.
Add lime or yuzu juice for a light citrus pop.
Set the heat level: Add red pepper flakes or chili oil a little at a time. Taste and adjust to your preference.
Rest briefly: Let the sauce sit for 5–10 minutes. This helps the ginger and garlic mellow and the flavors meld.
Use or store: Toss with fresh, sushi-grade fish or tofu right before serving, or pour into a clean jar for later.