Halve cucumbers lengthwise and scoop out seeds with spoon; discard seeds. Finely dice 1/4 cup (60 mL) cucumber and reserve for garnish. Cut remaining cucumber into chunks.
In blender, combine cucumber chunks, yogourt, 3 tbsp (45 mL) olive oil, lemon juice, shallots, garlic, chopped dill, salt and pepper. Puree smooth. Refrigerate about 2 hr. until cold.
Meanwhile, preheat oven to 400ºF (200ºC). Toss bread cubes with remaining oil. Arrange in single layer on parchment paper-lined baking sheet. Bake 8 min., or until crisp. Cool completely.
Divide soup into 4 bowls. Top with reserved finely chopped cucumber, croutons, dill sprigs and a drizzle of olive oil.
Substitute rye bread with multigrain, baguette or sourdough bread.