1. Chop the onion and bell pepper into slices and dice the tofu or tempeh.
2. Stir together all sauce ingredients in a small bowl.
3. In wok or large frying pan, heat coconut oil over medium heat. Add onion and cook, stirring often, until golden, about 8 minutes.
4. Add bell peppers, green beans and tofu or tempeh, increase heat to medium high and stir, fry for 5 minutes. Add tomatoes (with liquid) and pineapple chunks and stir, fry 5 minutes.
5. Stir in the sauce and cook, stirring, until mixture has thickened slightly, around 2 to 3 minutes.
6. Serve with wholegrain noodles or brown rice cooked to packet instructions.