Spray a small baking sheet with cooking spray. Place chicken breasts on the sheet and sprinkle lightly with salt and pepper.
In a small bowl mix together the mustard, garlic, 2 tablespoons grapeseed oil, salt and thyme. Stir well to combine. Spread about 2 teaspoons of the mixture on each of the chicken breasts reserving about 1 tablespoon of the mixture for the salad.
Place chicken breasts in the oven and bake for 20-25 minutes, or until done. Remove and allow to cool slightly.
Meanwhile add the pumpkin to a large rimmed baking sheet and sprinkle with the chili powder, crushed red pepper flakes, grapeseed oil and salt and pepper to taste. Bake at 425 for 40 minutes, or until fork tender. Remove and allow to cool slightly.
In a medium saucepan, bring the water to a boil. Add the quinoa and 1/2 teaspoon of salt and bring back to a boil. Turn to medium low and cook for 15 minutes, or until all of the water is absorbed. Add to a large serving bowl and add the pumpkin, arugula, crotin and salt and pepper to taste.
Add 1/2 cup of grapeseed oil and the 1 tablespoon of balsamic vinegar to the reserved mustard mixture and whisk to combine. Add to the quinoa mixture and toss lightly to coat. Slice the chicken breasts and top the salad. Serve immediately.