1.Boil, steam or microwave kumara until tender; drain. When cool enough to handle, peel kumara; cut flesh into 1.5cm pieces.
2.Meanwhile, blend or process oil, onion, cumin, ground and fresh coriander, chillies, rind, juice and the water in a food processor until smooth. Transfer to a small bowl; stand until required.
3.Drain oil from tomatoes over a bowl; reserve. Coarsely chop tomatoes. Process tomatoes and 2 tablespoons of the reserved oil with garlic and onion powders, paprika and nuts until coarsely chopped. Add 2 tablespoons of coriander mixture; pulse until combined.
4.Transfer tomato mixture to a large frying pan, stir in kumara. Heat mixture over low heat for 5 minutes or until warmed through. Serve kumara mixture in tortillas with rocket and remaining coriander mixture.