In a large saute pan or wok, heat the canola oil over medium-high heat. Add the green beans and cook for 5 minutes.
Add the onion, garlic, soy sauce, vinegar, chili paste, and cumin and saute for 3 to 5 minutes or until onions are fragrant but still hold their shape.
Add the tomatoes and cook for 1 to 2 minutes. Remove the pan from the heat and add the cilantro. Stir gently to combine. Serve warm.