In a non-stick skillet, add the sesame seeds and toast them on medium-low heat until they are golden brown. Stir frequently, they will brown quickly, so keep your eye on them, it only takes 1-3 minutes.
Add the toasted sesame seeds to a mortar and grind with a pestle until most of the seeds are finely crushed, but some remain. Set aside.
In a small mixing bowl, whisk the vegan mayo, sesame oil, soy sauce, rice wine vinegar, agave, mirin, and a pinch of black pepper until the dressing is smooth.
Pour the mashed sesame seeds into the bowl and whisk again to combine. Taste and adjust seasonings.
Store in the fridge unti ready to use.