Make the dressing. In a jar with a sealable lid, or a mixing bowl, zest ½ of the orange using a microplane grater. Next grate the garlic using the same grater and add it to the jar. Pour in the vinegar and let sit for a few minutes (I like to use this technique of letting the garlic “cook” a bit in the acid, which takes the sharp edge off). Add the honey, salt and pepper, and olive oil. Shake to combine, or whisk if using a bowl, and set aside.
Cut the fennel in half lengthwise, and then into thin slices. Lay in the serving bowl. Next add the chicken, then peel the orange and cut the segments into two or three pieces each, adding them to the bowl. Cut the avocado in half, removing the pit. Cut it longways into ½ inch pieces, then scoop them out with a spoon and add to the salad. Squeeze the lemon over the ingredients, making sure to get the avocado so it resists turning brown. Gently tear the herbs and layer on top, and the jalapeno if using.
At this point, the salad and dressing can be prepared and put in the refrigerator for up to 6 hours. Before serving, whisk or shake the dressing and drizzle evenly over the salad.