Begin by dicing the English cucumber into small cubes and placing them into a medium bowl. Sprinkle the diced cucumber with a pinch of salt to draw out excess moisture. Let it sit for about 10 minutes.

In a larger mixing bowl, combine low-fat Greek yogurt, crumbled feta cheese, chopped dill and chives, lemon juice, grated lemon peel, and a dash of black pepper. Stir these ingredients together until well blended.

After allowing the cucumbers to sit, drain any accumulated moisture using a fine-mesh strainer or by pouring them into a colander. Pat the diced cucumbers dry with paper towels.

Gently fold the drained cucumbers into the yogurt mixture with a spatula until all the cucumber pieces are coated evenly.

Select two slices of your favorite whole-grain bread and layer a handful of alfalfa sprouts on one slice. Generously spread the cucumber-yogurt mixture on top of the sprouts, and then add thin slices of red onion. Place the other slice of bread on top.

To preserve freshness, cut the sandwiches in half and serve immediately. These sandwiches are best enjoyed as soon as they're assembled.