In a large bowl, mash beans, mushrooms, onion, panko, miso, garlic powder, paprika, 1 tablespoon tahini, and ¼ teaspoon salt until combined and mixture clumps together. Form bean mixture into 8 patties about 2 ½" in diameter.
Lightly coat an air-fryer basket with cooking spray. Working in batches, arrange patties in basket, spacing about ¼" apart; generously spray with cooking spray. Cook at 400°, flipping halfway through, until crispy and browned on both sides, about 15 minutes.
Meanwhile, in a medium bowl, whisk dill, water, vinegar, and remaining 2 tablespoons tahini and ¼ teaspoon salt until smooth and drizzleable. If dressing is too thick, whisk in more water until desired consistency is reached.
Drizzle fritters with tahini dressing. Top with tomatoes and cucumbers.
