Heat oil in wok over high heat. Add bell peppers, ginger, and garlic; sauté until peppers just begin to soften, about 2 minutes. Add tofu and green onions; toss 2 minutes. Add next 3 ingredients. Toss to blend, about 1 minute. Add spinach in 3 additions, tossing until beginning to wilt, about 1 minute for each addition. Mix in basil. Season with salt and pepper. Sprinkle peanuts over.