Heat 1 tablespoon of the oil in a large skillet over medium heat. Add the onion, carrot and celery, season with salt and pepper, and sauté for 4 to 5 minutes until the vegetables are just barely tender. Turn the mixture into a large bowl, and add the lentils.
While the vegetables are cooking, in a small bowl or a container with a lid combine the remaining olive oil, vinegar, honey or other sweetener, lemon juice and zest, and salt and pepper. Stir or shake well. Pour the dressing over the lentil mixture and toss to combine. Cool to room temperature.
Peel and dice the avocados. Add the avocado, parsley and scallions to the salad and toss gently to combine. Serve at room temperature.