To prepare curry, combine first 6 ingredients in a food processor; process 3 minutes or until a paste forms.
Heat 1 teaspoon oil in a large Dutch oven over medium-high heat. Add chile mixture; sauté 3 minutes. Add bell pepper and next 5 ingredients (bell pepper through coconut milk); bring to a boil. Cover, reduce heat, and simmer 10 minutes. Uncover and simmer 10 minutes. Stir in lime juice and 1 teaspoon salt, and keep warm.
To prepare crabs, combine cornstarch and 1/4 teaspoon salt in a shallow dish. Dredge crabs in cornstarch mixture.
Heat 2 teaspoons oil in a large nonstick skillet over medium-high heat. Place 3 crabs in pan, top sides down; cook 3 minutes, gently pressing body and legs against pan. Turn crabs; cook 2 minutes. Remove from heat. Repeat procedure with remaining oil and crabs.
Place 1/2 cup jasmine rice into each of 6 shallow bowls; spoon 3/4 cup curry mixture over each serving. Top each serving with 1 crab. Garnish with lime wedges and cilantro sprigs, if desired.