To prepare the dressing, add the lemon juice, garlic, olive oil, and salt and pepper in a jar with a lid and shake vigorously until the ingredients are combined or whisk all the ingredients together in a small bowl.
In a salad bowl, pour the dressing over the fennel.
Add the radishes, scallions, lettuce and arugula.
Toss the salad.
Serve the salad with orange slices and the chopped mint on top.