Combine sweet chili sauce, soy sauce, garlic, cilantro, and (optional) ginger in a bowl and whisk til smooth and well mixed. Reserve half of the sauce and set it aside.
Add salmon fillets to the bowl with 1/2 of the sauce and toss to coat well. (If desired, you may marinate this for 30 minutes - overnight, but marinating is not necessary)
Cook the salmon either on a nonstick skillet for 4-6 minutes on each side, or in the oven turned to broil for the same amount of time. Cook until fillets are pink and easily flake with a fork.
Assemble tacos with cabbage (or cole slaw), mango slices, salmon, and top with remaining reserved sauce and drizzle with fresh lime juice. Serve immediately.