Step 1: In a medium saucepan, combine the rinsed quinoa and vegetable broth. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes or until water is absorbed. Fluff with a fork and set aside.
Step 2: In a small bowl, whisk together 2 tablespoons of olive oil, half of the lemon juice, minced garlic, red pepper flakes, salt, and pepper. Toss the shrimp in this marinade and let sit for 10 minutes.
Step 3: Heat a large skillet or grill pan over medium-high heat with the remaining tablespoon of olive oil. Add the shrimp and cook for 2-3 minutes per side until pink and opaque. Remove shrimp from the pan and set aside.
Step 4: In the same skillet, add the diced zucchini and corn. Sauté for 4-5 minutes until just tender but still crisp. Stir in the cherry tomatoes for the last minute of cooking.
Step 5: Assemble the bowls by layering the quinoa at the bottom, followed by the sautéed vegetables and grilled shrimp. Top with avocado slices and fresh cilantro.
Step 6: Drizzle the remaining lemon juice over the bowls and serve immediately.