Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper.
Toss sweet potatoes, bell peppers, and red onion with olive oil, salt, and pepper. Spread evenly on the prepared baking sheet.
Roast vegetables for 25-30 minutes, stirring halfway through, until tender and lightly caramelized.
While vegetables are roasting, whisk together all dressing ingredients in a small bowl.
In a large serving bowl, arrange mixed greens as the base.
Once vegetables are cooled slightly, layer them over the greens.
Add sliced avocado and cherry tomatoes.
Sprinkle with pumpkin seeds and drizzle with the prepared dressing.