Step 1Heat the oven to 300 degrees. Spread the pecans in a shallow baking dish and bake until crisp, about 10 minutes. Remove from the oven and cool, then chop coarsely. Raise the heat to 375 degrees.
Step 2Roll the pumpkin cubes in 1 tablespoon of the pumpkin seed oil in a large bowl and season with the aleppo pepper and salt. Spread on a large baking sheet and roast until they are soft and caramelized but still hold their shape, about 20 to 25 minutes, turning with a spatula every 5 minutes. Remove from the oven and cool to room temperature.
Step 3Whisk together the Sherry vinegar, mustard and minced shallot in a small bowl with salt and black pepper to taste. Whisk in the remaining oil until emulsified. Place the arugula in a salad bowl and drizzle the dressing over it to taste; you may not need it all. Toss until the greens are lightly coated.
Step 4Divide the greens among the serving plates and arrange the pumpkin cubes on top of each. Sprinkle with the blue cheese and toasted pecans and serve at once.