Preheat and prepare: Heat oven to 425°F. Toss 2 cups pumpkin cubes with 3 tablespoons olive oil, salt, thyme, pepper, and optional chili flakes thoroughly.
Roast pumpkin: Spread pumpkin on baking sheet in single layer. Roast 20-25 minutes, stirring halfway, until edges are golden and caramelized beautifully.
Cook quinoa: Rinse 1 cup quinoa. Combine with 2 cups vegetable broth and ½ teaspoon salt in saucepan. Bring to boil then reduce heat.
Simmer grains: Cover and simmer 15 minutes until liquid absorbs completely and quinoa becomes fluffy and tender throughout batch.
Prepare dressing: Whisk together 1 minced garlic clove, 2 tablespoons Dijon mustard, ¼ cup lemon juice, ⅓ cup olive oil, salt, and pepper.
Assemble salad: Layer 4 cups arugula in large bowl. Top with cooled quinoa, roasted pumpkin, ⅓ cup feta, ⅓ cup pumpkin seeds, and red onion slices.
Dress and serve: Drizzle dressing all over. Toss everything together gently. Serve immediately. ENJOY!!!