Prepare Vegetables: Wash cucumbers, peel if desired, and cut into chunks or slices. Chop onions and red pepper.
Salt and Soak: Place cucumbers, onions, and pepper in a large bowl. Sprinkle with coarse salt, mix well, and let sit for 1–2 hours. Rinse thoroughly and drain.
Cook Pickling Liquid: In a large pot, combine vinegar and sugar. Heat gently until sugar dissolves.
Make Mustard Sauce: In a separate bowl, whisk flour, dry mustard, and celery seed with a little cold vinegar to form a smooth paste. Slowly add to the hot vinegar mixture while stirring constantly to avoid lumps. Cook until thickened into a sauce.
Combine: Add the drained vegetables to the mustard sauce and stir well. Simmer gently for 20–30 minutes, or until vegetables are tender but not mushy.
Jar the Pickles: Spoon hot mixture into sterilized jars, leaving ½ inch headspace. Seal and let cool.
Serving and Storage Tips
