Dice 2 medium English cucumbers into small cubes, place in a colander, sprinkle with salt, and let sit for at least 15 minutes.

In a mixing bowl, combine 1 cup yogurt, ½ cup crumbled feta, ¼ cup chosen herbs, zest and juice of 1 lemon, and a pinch of ground pepper.

After 15 minutes, drain cucumbers again, pat dry with paper towels.

Transfer cucumbers to the yogurt mixture and stir well until coated.

Toast bread, then spread sprouts on one slice, add cucumber mixture, layer with onion (optional), and top with another slice.

Cut sandwiches diagonally and serve immediately.