Place shrimp in a ziplock bag with chili powder, lime juice, and olive oil. Make sure the shrimp is fully coated in mixture and let it marinate in the fridge for 20 minutes.
While shrimp is marinating, make salsa. In a medium bowl, combine mango, strawberry, avocado, onion, and black beans. Toss to combine.
Heat grill pan (or skillet) to medium heat and grill shrimp for about 2-3 minutes on each side, until pink. You may need to do this in two batches, moving the first batch of shrimp to a foil-covered bowl to keep warm while the rest of the shrimp cook.
Warm tortillas in oven or microwave. Top each with a little bit of fruit salsa, about 5 shrimp, and some feta cheese. Top with Greek yogurt and additional lime juice if desired.