Roast the vegetables: Preheat the oven to 400 degrees. Spread the peppers, zucchini, squash, and onion out on a lined baking sheet. Drizzle 1 tablespoon of olive oil over the top and sprinkle with 1 teaspoon each of salt and pepper. Roast the veggies in the oven for 20-25 minutes or until tender and slightly charred on the outside.
Make the Pea Pesto: Combine all the pesto ingredients in a food processor. Blend until the mixture is smooth. Set aside.
Assemble the bowls: Layer ½ cup quinoa into each bowl. Then, place equal amounts of veggies into each bowl. Top with ¼ cup pea pesto. Squeeze fresh lemon juice over the top and garnish each bowl with extra chopped pistachios.