I like arugula. I like radishes. I like grilled swordfish. So I thought — why not combine the three into a quick, easy, delicious 10-minute salad? With a zingy horseradish vinaigrette, this is a celebration of all things spring.
Preheat a grill or cast-iron grill pan on medium heat until smoking hot, about 5 minutes. Rub the swordfish with the olive oil and place on the grill until opaque along the sides and grill marks have appeared, about 8 minutes total.
Meanwhile, combine the mustard, vinegar, and garlic in a salad bowl and whisk in the extra-virgin olive oil. Season with salt and pepper, to taste. When the swordfish is done, add the arugula and radishes to the bowl and toss. Transfer the dressed salad to two plates and divide the swordfish equally on top.