Whisk jam, vinegar, oil, shallot, 1/4 teaspoon salt, and 1/4 teaspoon pepper in large bowl. Toss fennel with vinaigrette; let stand 15 minutes. Add arugula, fennel fronds, and grapes; toss and adjust seasonings with salt and pepper. Divide salad among individual plates; top each with portion of Gorgonzola and pecans. Serve immediately.