For the salsa: Toss the pears with canola oil. Place the pears on a hot grill or grill pan. Grill for 3 minutes per side. Remove from the grill and cool. Chop grilled pears into small pieces and place in a small bowl. Add red onions, garlic, jalapeno, oregano and lemon juice. Mix well. Season with salt and pepper. Refrigerate for 30 minutes before serving.
For the quesadillas: Preheat the oven to 350 degrees F. Mix together the duck confit, green onions and Gruyere cheese. Season with salt and pepper. Lay 3 of the tortillas on a flat surface. Spread the confit mixture evenly on each tortilla. Top each with another tortilla. Press down firmly. Brush the top of each quesadilla with some of the melted butter. Place the quesadilla on a baking sheet and bake for 10 minutes, or until tortilla is golden brown and the cheese is melted. Remove from the oven and slice into 4 pieces. Garnish each piece with a scant tablespoon of the grilled pear salsa and a dollop of creme fraiche.