For the tabbouleh: Place the bulghur wheat in a bowl and cover with water. Stir in the salt and soak for 40 minutes, or until the a bulghur is softened but still a bit crunchy. When ready, drain the water from the bulghur wheat, squeezing out as much moisture as possible with your hands.
Place the bulghur wheat in a large bowl and add the tomatoes, the parsley, the bacon and the cumin. Mix well. Add the lemon juice, the olive oil and the harissa. Mix well and taste for seasoning. Cover. Reserve in the refrigerator until ready to serve. Just before serving, moisten with a bit of olive oil.
For the taratour sauce: Combine all ingredients in a bowl. Beat in 1/2 cup plus 2 tablespoons cold water in a stream.