To make the miso tahini spread, whisk the ingredients together in a small mixing bowl till totally smooth. Spread will yield about 6-7 tablespoons and can be stored in an airtight container in the fridge for up to 10 days.
To make the sandwich, toast the bread, and spread a heaping tablespoon of miso tahini spread on each slice. Pile the toast with veggies, cut into halves, and serve.