1. Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).
2. In a large bowl, toss cauliflower florets with oil, pesto, lemon pepper seasoning, and salt. Spread onto two large baking sheets. Try to keep the florets from touching one another.
3. Place potato puffs into a nine- by 13-inch (20- by 30-centimeter) baking pan and spray lightly with cooking spray. Sprinkle with chili powder and place in oven together with cauliflower. Bake for 25–30 minutes, or until lightly browned. Flip pieces over midway through the baking to ensure even browning.
4. Toss tomatoes with oil, salt, and pepper and place in an additional baking pan, adding to the oven for the last 10 minutes of baking time.
5. While everything is roasting, whisk all dipping sauce ingredients together until well blended. Set aside.