In a large bowl, whisk together the mayonnaise, mustard and lemon juice. Add the radishes, mushrooms, cucumber and broccoli. Season with salt and pepper, then mix well. Add the arugula and gently toss to combine.
Divide the salad among small cups or ramekins.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.