Trim ends from cucumbers and slice into 1/4-inch-thick rounds. In a colander set over a plate, toss them with salt. Refrigerate, uncovered, for 2 hours. Drain and transfer cucumbers and dill to a bowl.
In a small saucepan, combine sugar, vinegar, coriander, peppercorns and allspice. Bring to a boil and cook until sugar dissolves. Pour hot liquid over cucumbers and toss well. Let stand, tossing every 10 minutes, for 30 minutes. Transfer to an airtight jar and refrigerate for up to 1 week.