In a bowl, combine diced mango, red onion, jalapeno, cilantro, and juice of 1 lime. Season with salt and pepper. Set aside to let flavors meld.
In another bowl, toss shrimp with olive oil, chili powder, salt, and pepper. Heat a skillet over medium-high heat and cook shrimp for 2-3 minutes per side until pink and cooked through. Remove from heat.
In a small bowl, mash the avocados with the juice of 1 lime. Season with salt and pepper.
To assemble the bowls, divide cooked rice or quinoa among serving bowls. Top with avocado mash, cooked shrimp, and mango salsa.
Drizzle with lime-chili sauce (optional) and garnish with additional cilantro. Serve immediately.