In a medium bowl, combine shrimp, olive oil, cumin, chili powder, salt, and pepper. Toss until the shrimp are well coated.
Heat a skillet over medium-high heat. Add the seasoned shrimp and cook for 2-3 minutes on each side until they are pink and cooked through. Remove from heat and set aside.
In another bowl, gently mix the diced mango, avocado, red onion, red bell pepper, jalapeño (if using), and lime juice. Season with salt and pepper to taste.
Warm the tortillas in the skillet for about 30 seconds on each side until pliable.
To assemble the tacos, place a few shrimp on each tortilla and top with the mango-avocado mixture.
Garnish with fresh cilantro and an extra squeeze of lime juice, if desired.