Cut radicchio into wedges leaving a thin piece of core attached to each wedge, set aside. Dice apple and place in large shallow bowl. In large skillet over medium heat, cook bacon until it is almost crisp and has rendered its fat. Remove bacon and reserve. If necessary, add olive oil to pan to make about 2 tablespoons fat. Add radicchio and sauté until slightly limp, about 1 1/2-2 minutes. Remove radicchio to bowl with apple. Stir vinegar, mustard, sugar, salt and pepper into pan drippings, heat through, stirring to dissolve sugar. Pour over radicchio and apple; toss. Serve immediately on salad plates, garnished with pecans.