Cucumber, Onion, Tomato and Tahini Sandwiches

In a small bowl, cover onion with ice water and refrigerate for 30 minutes, up to 1 day. When ready to use, drain onions thoroughly.

In a small bowl, stir together tomatoes, tahini, vinegar, miso and 1 to 2 tablespoons water if necessary to make a spreadable paste. Divide tahini mixture between toast slices, top with cucumbers, drained onions and sprouts. Serve immediately.