Put all but 4 of the grapes in a metal bowl and put it in the freezer. Tear the bread into chunks and chop it in a food processor until it’s reduced to fine crumbs. Put the crumbs in a small bowl, stir in 1/3 cup cool water, and set aside. Toast the almonds in a dry skillet over medium-low heat, stirring frequently, until deep golden brown, 10 to 12 minutes. Transfer to a plate to cool.
Meanwhile, prepare the other ingredients: Slice the 4 grapes in half. Cut off and discard the cucumber ends. Thickly slice the cucumber. Slice the scallions. Slice the garlic. Chop the dill.
In a food processor, chop the garlic and 1/4 cup of the almonds until very fine. Add the breadcrumbs and cream cheese and process until well blended. Add the cucumber, scallions, dill, milk, vinegar, and the grapes from the freezer. Process until puréed as finely as possible, 1 to 2 minutes. With the machine running, pour in the oil. Taste and season with salt and pepper. Serve garnished with the grape halves and the remaining almonds.