Place fish in a medium glass dish. In a small bowl, combine 1 cup plain, whole milk Greek yogurt, 1 teaspoon chili powder, 1 teaspoon garam masala, 1 teaspoon fresh ginger, 2 cloves garlic, ⅛ teaspoon cayenne pepper, and ½ teaspoon sea salt until well blended.
Cover 4 white fish fillets with yogurt marinade. Cover dish in plastic wrap, and allow to marinate in the refrigerator for about 2 hours.
In a large skillet over medium heat, melt 2 tablespoons butter.
Remove fish from marinade and shake off any excess. Place fish in skillet and cook for about 5 minutes on one side, then flip and cook for an additional 2-3 minutes or until fish is opaque and flakes easily.
Meanwhile, combine 1 mango 1 kiwi, ½ cucumber, ⅓ cup hearts of palm (all diced), ½ teaspoon lime zest, 2 tablespoons fresh lime juice and ¼ teaspoon sea salt. Toss together until fully combined.
Spoon over cooked fish or serve alongside.