Cut each block of tofu in half lengthwise. Place tofu slices on several layers of paper towels; cover with additional paper towels. Let stand 30 minutes, pressing down occasionally. Cut tofu into 1/2-inch cubes.
Heat grapeseed oil in a large nonstick skillet over medium-high heat. Add garlic, ginger, and chiles; stir-fry 30 seconds. Add bell pepper, and cook 3 minutes or until tender, stirring frequently. Stir in tofu and sherry; cook 3 minutes or until heated through, stirring frequently. Stir in onions; cook 30 seconds. Remove from heat; stir in soy sauce, bean paste, and sesame oil, stirring gently to combine.