Bring a pot of water to boil. Place crab claws in a strainer and lower it into the boiling water. If crab claws are precooked, allow them to heat through for 1 to 2 minutes. If crab claws are raw, allow them to cook until shells turned red. Depending on the size, it should take between 2 to 5 minutes.
When crab claws are cooked, lift strainer from boiling water and allow it to drain. Arrange crab claws to one side on a large platter.
Heat 1 tablespoon vegetable oil over medium high heat. Sear cauliflower florets for 2 to 3 minutes. Remove and place to one side on a large platter. Do the same with sweet and green bell peppers.
Heat remaining 2 tablespoon vegetable oil to the wok. Saute chopped red chili, ginger, black beans, and garlic for 2 minutes. Pour in cornstarch mixture and allow it to come to a boil. Sauce will thicken. Season with salt. Turn off stove.
Pour sauce over crab claws and seared vegetables.