1/2 pound assorted mushrooms, such as shiitake and cremini, stems trimmed, thinly sliced
Coarse salt and ground pepper
1/2 cup grated fontina cheese (1 1/2 ounces)
1 cup arugula, trimmed and washed
1/2 teaspoon fresh lemon juice
On a work surface, layer salami on half the tortilla. In a large nonstick skillet, heat 1 teaspoon oil over medium-high. Add mushrooms and cook, stirring occasionally, until golden brown, 8 minutes. Season with salt and pepper.
Place mushrooms and cheese on top of salami; fold tortilla over filling. Place quesadilla in skillet and cook over medium until tortilla is golden brown and cheese is melted, about 3 minutes per side. Transfer quesadilla to a cutting board and cut into 3 wedges.
In a small bowl, toss arugula with lemon juice and 1/4 teaspoon oil. Season with salt and pepper and serve alongside quesadilla.