To make mango salsa, combine mango, red onion, cilantro and remaining ingredients in a medium mixing bowl. Fold ingredients together to combine. Season with salt and pepper. Cover and refrigerate until ready to assemble tacos.
Salmon Tacos
To prepare tacos, combine soy sauce, garlic and maple syrup/honey in a small mixing bowl. Stir until incorporated. Pour marinade on salmon fillets and marinade under refrigeration for 30 minutes, up to overnight.
Prepare grill by setting to medium-high heat. Lightly brush grates with oil to prevent sticking. after marinading, transfer salmon fillets to grill top side down. Grill until bottom of fillets begin to turn an opaque color, about 2-3 minutes. Use a spatula to gently flip fillets. Repeat the grilling process for another 2-3 minutes, or until cooked thoroughly. Promptly remove salmon fillets and transfer to a heat safe platter after grilling to prevent overcooking.
Meanwhile, warm tortillas. Bring a medium sized pan to low heat. Heat each tortilla by transferring to the pan one a a time until heated through. Cover heated tortillas with a towel to prevent drying out.
To Assemble
To assemble tacos, place 1 romaine lettuce leaf atop each tortilla. Add a spoonful of black beans to each taco then top with one salmon fillet. Spoon mango salsa atop each taco and garnish with cilantro sprigs. Serve immediately.