In an iron skillet, without oil, toast the celery and cumin seed for a few seconds until you get a good whiff of the spice aroma. Remove the spices from the heat and transfer them to a mixing bowl. Whisk in the sugar and yogurt.
Add the cucumbers and cabbage and toss well to combine. Cover and refrigerate until ready to serve. Right before serving, give the cole slaw a toss, taste and season with salt and a dash of cayenne pepper. If it does not taste "tangy enough, add drops of white wine vinegar and keep on tasting.