Heat oven to 200C/180C fan/ gas 6. On a baking tray, toss the sweet potato in 1 tbsp of the oil with the chilli flakes, sea salt and pepper. Roast for 30 mins until tender.
Once the sweet potato is nearly ready, combine the remaining ingredients in a large bowl with the remaining 1 tbsp oil and season well. Mix everything well but take care to avoid squashing the avocado. Divide the salad evenly between plates, or serve sharing-style with the sweet potato chunks.