Whisk honey, soy sauce, rice vinegar, sesame oil and grated ginger in a small bowl until smooth.
Mince the garlic finely and set aside.
Heat a small saucepan over medium heat and add the mixed sauce ingredients.
Bring the mixture to a gentle simmer, stirring to combine.
Add the minced garlic and optional red pepper flakes, simmer 1–2 minutes to release aroma.
Stir the cornstarch slurry again and slowly stream it into the simmering sauce while stirring.
Continue stirring; the sauce will thicken and become glossy within 1–2 minutes.
Taste and adjust: add a splash of water to thin or extra vinegar to brighten the flavor.
Remove from heat once the sauce reaches a glossy coating consistency; it will thicken further as it cools.
Toss with cooked tofu, chicken, salmon, or vegetables, and garnish with sesame seeds and sliced green onion.