Juice the lemons, orange, and shallot in a juice extractor. Put the juices in a bowl and whisk in the olive oil in a slow stream to form an emulsion. Season with the salt and pepper. Taste and adjust the seasoning. Whisk again, cover, and refrigerate for up to 3 days. You should have about 2 cups.
Just before serving, place the greens in a salad bowl, add about 1/2 cup vinaigrette, and toss well. Add more to taste and adjust the seasoning. Finish the salad with a sprinkling of cocoa nibs to taste.
Variation for Blender: Use 3 lemons, 2 small oranges, 1 shallot, 1 teaspoon gray salt, 1/2 teaspoon pepper, and 1 1/2 cups pure olive oil. Cut off and discard the stem ends of 2 lemons and 1 orange. Cut into quarters, cut out the core, and remove seed. Place in a blender. Squeeze the juice from the remaining lemon and orange; add to the blender with the shallot, salt, and pepper. Pulse and then blend the fruit until as smooth as possible. With the machine running, add the olive oil in a thin, steady stream. The vinaigrette will be thick like a mayonnaise. If it is too thick, with the machine still on, thin with a little hot water. Taste for seasoning. Cover and refrigerate for up to 3 days. If the vinaigrette separates, return it to the blender and blend until smooth again. Makes about 3 cups.