Heat a grill to medium-high (about 450°). Quarter pears lengthwise; stem and core. Toss pears in a bowl with 1 tbsp. oil; season with 1/4 tsp. each salt and pepper. Grill pears until lightly charred, 2 to 3 minutes per side.
Meanwhile, tear radicchio, frisée, and endives into 2- to 3-in. pieces. You should have about 12 cups.
In a large bowl, whisk together vinegar, mustard, and remaining 1/2 tsp. salt and 1/4 tsp. pepper. Slowly whisk in remaining 1/2 cup oil.
Combine parsley, walnuts, and ricotta in a food processor; pulse until coarsely ground.
Toss warm pears and chicories in vinaigrette. Spread about 2 tbsp. walnut-ricotta mixture on each of 4 plates, then top with salad. Scatter remaining walnut-ricotta mixture over salads.