Prep the rice: Have 1½ cups cooked rice ready. If you don’t have cooked rice, bring a pot of lightly salted water to a boil. Add ½ cup uncooked rice and cook according to package directions. Drain if needed and set aside.
Roast the vegetables: Preheat oven to 400°F (200°C). Add 1 pound sweet potatoes (peeled and diced), 1 bell pepper (chopped), and 1 onion (sliced) to a large baking sheet. Drizzle with olive oil. Add 1 teaspoon smoked paprika, 1 teaspoon cumin, 1 teaspoon salt, and black pepper. Toss well and spread into a single layer. Bake for 25 to 30 minutes, until tender and lightly browned on the edges.
Make the sauce: While the vegetables roast, blend 1 cup Greek yogurt, ½ cup fresh cilantro, 2 tablespoons lime juice, 1 tablespoon olive oil, ½ clove garlic, 1 tablespoon maple syrup (if using), ½ teaspoon salt, and 3 tablespoons water until creamy. Don't overblend. The dressing should be pourable.
Add beans and rice: Remove the baking sheet from the oven. Add 1 can black beans (drained), ½ cup corn, and ¼ cup pickled jalapeños directly to the pan. Season with a couple pinches of salt and black pepper. Squeeze ½ a lime over everything. Toss well so the rice and beans pick up the roasted flavors.
Serve: Spoon into bowls. Top with diced avocado and pickled jalapeños. Drizzle generously with the sauce. Add crumbled feta if desired. Serve warm.
