Preheat a grill or grill pan to medium high. Toss the radicchio, fennel wedges and bell peppers in a large bowl with 1/4 cup olive oil. Season with salt and pepper and grill, turning occasionally, until charred and crisp-tender, about 4 minutes for the peppers and radicchio, 6 minutes for the fennel. Remove from the grill and let cool, then cut into small pieces.
Bring a large pot of salted water to a boil. Add the pasta and cook until al dente (about 2 minutes less than the label directs). Drain and rinse under cool water; shake off the excess. Transfer to a serving bowl. Add the grilled vegetables, cannellini beans, the remaining 1/4 cup olive oil, the lemon juice, parsley, 1/4 teaspoon salt, and pepper to taste; toss. Add the parmesan shavings and fennel fronds and toss gently. Serve immediately or refrigerate, covered, up to 6 hours. (Bring to room temperature before serving.)