Preheat the broiler and position the oven rack so the fish will be about 6 inches from the broiler heat.
Heat 1/2 teaspoon of the dark sesame oil in a large nonstick skillet over medium heat.
Add the minced fresh ginger, minced garlic, finely chopped red bell pepper, and chopped scallions to the skillet; cook, stirring, about 1 minute.
Stir in the curry powder, red curry paste, and ground cumin; cook, stirring, 1 minute.
Add the low-sodium soy sauce, brown sugar, Asian fish sauce, and the light coconut milk; bring the mixture to a gentle simmer (do not boil), then remove the skillet from the heat.
Stir the chopped fresh cilantro into the sauce and set the sauce aside, keeping it warm.
Coat a baking sheet with cooking spray. Pat the tilapia fillets dry, brush them with the remaining 1/2 teaspoon dark sesame oil, and lightly sprinkle with salt.
Arrange the fillets on the prepared baking sheet and broil for 7 minutes or until the fish flakes easily when tested with a fork.
Transfer the broiled fillets to plates and spoon the Thai coconut curry sauce over each fillet. Serve immediately.