Wash the cauliflower and break into small flowerettes. Wash, seed and halve the peppers, cutting them into 1/4-inch crosswise slices (rings). Pour boiling water over the onions, let stand for 5 minutes, then skin. (pare.) Wash the tomatoes and cut them into eighths. Mix the cauliflower, peppers, onions, tomatoes, whole and sliced cucumbers in a large bowl. Cover with the salt and cold water combined. Let stand for 16 hours, then place the mixture in a large kettle and bring just to a boil, then drain. Meanwhile, heat the vinegar, sugar and celery seed to boiling. Mix the flour and the rest of the ingredients into a paste. Stir into the vinegar mixture, blending well. Add the drained vegetables and cook, uncovered, for 20 minutes, stirring constantly. Turn at once into clean hot sterilized preserve jars and seal at once as the manufacturer directs. Process in a hot water bath according to your conditions.