For 4 Person(s)
To make vinaigrette: In a small bowl or jar, combine canola oil, lemon juice, vinegar, garlic, mustard, marjoram, salt and pepper. Whisk to combine. Let sit for at least 30 minutes, or make the dressing a day in advance. Discard the garlic before using.
In medium steamer pot, add ½ cup (125 ml) water to bottom of pot and green beans to steamer. Steam the beans until crisp-tender, about 4 minutes. Drain and plunge into ice water to stop the beans from cooking further, drain again once they have cooled. Set aside.
Using the same steamer pot, steam the potatoes until tender when pierced with a knife, about 10-15 minutes. You may need to add additional water to complete steaming. Drain.
In a large bowl, add warm potatoes and drizzle with about 1/3 of the vinaigrette. Set aside until cooled completely.
Add chickpeas, tomatoes, mozzarella, and remaining vinaigrette. Toss. Add the green beans just before serving and garnish with basil.
The acidity of the dressing will cause the green beans to discolour after a couple of hours, much as a pickled green bean loses its bright colour. Adding the green beans shortly before serving the salad will keep the dish visually appealing.
Leftovers will keep well in the refrigerator for two or three days, and taste fine despite the lack of colour.