Heat canola oil in a skillet over low heat. Add minced garlic; cook just until fragrant, being sure not to brown. Add dark sesame oil, soy sauce, honey, rice wine vinegar, creamy peanut butter, and boiling water, stirring constantly until thick, smooth, and hot. Cook spaghetti according to the package directions. Toss pasta and sauce together; top with scallions and crushed red pepper. Serve immediately.