Peel, and slice the onion and the red pepper into long strips. You do not need to peel the sunchokes, just trim, wash and slice into bite-sized pieces.
Place the cut sunchokes in a bowl.
Pour some olive oil over them and toss to coat well. Preheat the air fryer or oven, or you can even use a frying pan with oil. Add the sunchokes when ready, and cook, tossing about every 5 minutes
In a frying pan, over medium high heat, add the olive oil, then add the sliced onions, and salt. Sauté for 3 or 4 minutes, then add the sliced peppers.
Continue to cook until the vegetables are done to your liking (I sauté for another 8-10 minutes.) Add more salt, taste, and adjust as needed.
The sunchokes should be ready at this time, remove from the air fryer, add salt as desired, then add them to the pan of vegetables.
Toss gently to mix well. Taste for salt and add if needed; also add pepper, if desired.
Transfer to a warm serving dish and serve immediately.