Place the bulgur in a strainer or colander, shake out any debris, rinse under cool water, and set the strainer with the grain in it in a large bowl. Cover with water and set aside for 10 minutes. Drain off the water, wrap the bulgur in a clean kitchen towel, and twist to squeeze out excess moisture. While the bulgur soaks, add a pinch of cinnamon to the dressing and set aside briefly. Put the bulgur in a large, wide glass or ceramic bowl and pour the dressing over it. Scatter the scallions over the surface of the bulgur; add the parsley, cilantro, and mint, and end with the sorrel. Top with the avocados, cover tightly with plastic wrap, and refrigerate for several hours before serving. To serve, use two large salad spoons or forks to toss the ingredients together, being sure to reach to the bottom to incorporate the bulgur and its dressing. Taste, and correct for salt and pepper as needed. Serve immediately, or refrigerate, covered, for up to 3 days. Serve cold or at room termperature.