Toast the sesame seeds in a dry skillet over medium heat, shaking frequently, until golden and fragrant, about 3 to 4 minutes. Transfer to a plate and cool completely.
Add the sesame seeds, tahini, miso, rice vinegar, mirin, soy sauce, sesame oil, ginger, and garlic to a blender. Blend until smooth, about 1-2 minutes.
With the blender running, stream in the neutral oil slowly, or add it in batches, stopping the blender each time to scrape down the sides.
Add 2 to 4 tablespoons cold water, one tablespoon at a time, until the dressing reaches a pourable consistency. Taste and adjust seasoning.
Top with more sesame seeds right before serving.
Serve with salads, or as a dip with snap peas, radishes, or endive leaves. You can also serve the sauce with satay dishes.