Cook spaghetti in a 6- to 8-quart pot of boiling salted water until al dente. Drain in a colander, then rinse well under cold water and transfer to a large bowl.
Heat vegetable oil with red pepper flakes in a small saucepan over moderate heat until hot, then whisk in coriander, ginger, soy sauce, and salt (sauce will sizzle). Add sauce to spaghetti along with remaining ingredients and toss until combined well. Serve at room temperature.
