Begin by dicing the English cucumbers into small cubes, sprinkle them with salt and place them in a colander to drain for at least 15 minutes.

While cucumbers are draining, combine yogurt, crumbled feta cheese, fresh herbs, lemon zest, lemon juice, and a pinch of black pepper in a mixing bowl.

After letting the cucumbers sit, toss them to ensure they released moisture, then drain and pat dry with paper towels.

Add the drained cucumbers into the yogurt-feta mixture and gently fold everything together.

Toast slices of bread until golden brown. On one slice, layer sprouts, then scoop on the cucumber salad mixture, followed by onion slices if desired, and top with another slice of bread.

Slice the sandwiches in half for easy handling and serve immediately.