Trim the stems from the figs and discard. Cut each fig into 6 to 8 pieces. In a small saucepan, heat the port until hot to the touch, remove from the heat, and add the figs. Let the figs soak in the port until softened, about 2 hours. Put the figs and port in a food processor or blender and purée until smooth. Strain the mixture through a sieve, pushing on the solids with a spatula; discard the solids. Stir enough water (about 1/4 to 1/3 cup) into the purée to thin it to a dressing consistency. Season to taste with salt and pepper; set aside.
Whisk together the oil, vinegar, and shallots. Season to taste with salt and pepper; set aside.
Cut the endive and radicchio into 1-inch wide strips, discarding the hard cores. (It isn’t usually necessary to wash these salad greens.)
Remove the core from the pear, cut into thin wedges, and toss with lemon juice. Toss the endive, radicchio, and pears with the cider vinaigrette. Divide among six salad plates. Drizzle the fig and port dressing over the salads. Top each salad with a slice of Cabrales and serve immediately.