Heat 1 tablespoon olive oil in a saucepan over medium-low heat. Cook and stir leeks until soft, 10 to 15 minutes.
Remove to a plate and allow to cool.
Place cucumbers in a blender with grapes, almonds, 1 tablespoon olive oil, salt, creme fraiche, bread cubes, vinegar, cooled leeks, and water. Puree until smooth, about 1 minute. Strain through a fine mesh sieve. Cover and chill for 1 to 2 hours.
Taste and season with salt and cayenne pepper. If needed, add some more vinegar.
Serve garnished with dill oil (see note), thinly sliced grapes, slivered almonds, and fresh dill.