Cook couscous according to package directions. Combine with mango, jalapeno pepper, 1 teaspoon of the lime juice, and half the cilantro. Season to taste with salt and black pepper.
In a large bowl, whisk together red curry paste, vegetable oil, 1 tablespoon of the garlic, and remaining lime juice. Add shrimp; toss to coat.
Mix together yogurt, ginger, and remaining cilantro and garlic in a small bowl. Season to taste with black pepper.
Heat a grill to medium high. Grill shrimp until just cooked through, about 2 minutes per side.
Arrange shrimp and couscous on a platter and serve with the yogurt sauce. Garnish with lime wedges if desired.