Prepare the Shrimp: In a medium bowl, combine olive oil, minced garlic, smoked paprika, chili powder, cayenne pepper (if using), salt, pepper, and lime juice. Add shrimp and toss to coat. Cover and refrigerate for 15-30 minutes.

Cook the Rice: Rinse rice until water runs clear. In a medium saucepan, combine rice, water, salt, and olive oil (if using). Bring to a boil, then reduce heat to low, cover, and simmer for 18-20 minutes, or until water is absorbed. Remove from heat and let stand, covered, for 5-10 minutes. Fluff with a fork.

Prepare the Black Beans: In a medium bowl, combine rinsed and drained black beans, chopped red onion, lime juice, cumin, salt, and pepper. Stir well. Set aside.

Make the Corn Salsa: In a medium bowl, combine thawed corn, chopped red bell pepper, chopped red onion, chopped cilantro, lime juice, minced jalapeño (if using), salt, and pepper. Stir well. Set aside.

Create the Avocado Crema: In a blender or food processor, combine avocado, sour cream (or Greek yogurt), lime juice, water, salt, and garlic powder. Blend until smooth and creamy, adding more water as needed to reach desired consistency.

Grill the Shrimp: Preheat grill to medium-high heat. Thread shrimp onto skewers (optional). Grill for 2-3 minutes per side, or until pink and opaque.

Assemble the Bowls: Divide rice among bowls. Top with black beans, corn salsa, and grilled shrimp. Drizzle with avocado crema. Add optional toppings. Serve immediately.