This is a beautiful dish, which I discovered on vacation with my family in Capri. Every year, we visit the same hotel—Hotel Quisisana—on this beautiful island in southern Italy. The region is rich in seafood, which they use for everything from antipasti to entrées. Some of the seafood can be a bit exotic for most American palates, especially squid. But don’t be afraid of it: You can buy squid that’s already cleaned from your fishmonger, and all you need to do is rinse, grill, and slice. Just like chicken. (Okay, not really just like chicken, but the steps are the same.)
In a Small, heavy skillet, heat the oil over a medium flame. Add the garlic and herbs, and sauté until fragrant, about 30 seconds. Cool to room temperature, then whisk in the lemon juice and ½ teaspoon each of salt and pepper. Set the dressing aside.
Prepare a charcoal or gas grill for medium-high heat or preheat a ridged grill pan over a medium-high flame. Pat the scallops and squid dry with paper towels, then brush them with 2 tablespoons of the dressing and sprinkle with ½ teaspoon each of salt and pepper. Thread the scallops onto skewers and grill the scallops and squid until just cooked through, turning once, about 2 minutes per side. Cool completely. Remove the scallops from the skewers and cut the squid crosswise into ¼-inch-wide rings.
In a large bowl, combine the beans, arugula, carrots, and bell pepper. Toss with enough dressing to coat. Season with more salt and pepper to taste.
Place 1 large or 2 medium radicchio leaves on each of 4 plates. Spoon the bean salad into the radicchio cups, and top with the scallops and squid. Drizzle the remaining dressing over and serve.