Peel cucumbers and slice lengthwise. Remove seeds and slice.
Lay sliced cucumbers on a sheet pan covered with 2 layers of paper towel. Salt cucumbers liberally. Let them "sweat", about 20 minutes, to release moisture.
In a blender or food processor, blend cucumbers, yogurt, shallot, garlic, fresh dill, lime or lemon juice and ground cumin.
Puree until smooth, about 1 minute.
Check seasoning and add salt if necessary. Chill at least an hour before serving.
