Preheat the oven to 375. Pour out one cup of salt onto a baking sheet and arrange the beets over top. Cover with the remaining salt, and gather it around the sides to enclose the beets as much as possible. Roast for about 90 minutes, or until a knife can easily be inserted into the beets. Allow to cool, then peel and grate using the large holes of a box grater.

Make the tahini dressing by grating the clove of garlic into a bowl. Add the lemon juice, tahini and cumin, then whisk to combine. The tahini will seize up - this is totally normal. Add cold water to the mixture, one tablespoon at a time, and whisk until you get a nice, smooth, slightly thick sauce.

Mix the grated beets with the tahini dressing, olive oil, dill and mint. Taste for seasoning, and add more salt only if needed. The beets will already be well seasoned from roasting in salt. Add more lemon juice if desired. Serve warm, room temperature or cold. This salad will keep for up to 5 days in the fridge.