Heat your oven to 200°C/Fan 180°C/Gas 6. Line a baking tray with baking paper. Scrub the sweet potatoes and chop them into 8 wedges each. Pop on the tray.
Sprinkle the wedges with a pinch or two of cayenne (it's spicy, so use as much or as a little as you like) and drizzle with 1 tbsp olive oil. Season with salt and pepper. Turn to coat in the oil and spices. Bake for 40 mins, turning once, till tender.
Meanwhile, toast the sunflower seeds in a dry frying pan for 2-3 mins till brown and starting to pop. Tip them onto a board and cool a little, then roughly chop. Set to one side.
Finely grate the zest from the lime. Roughly chop the chives and coriander (stalks and leaves). Quarter the baby plum tomatoes. Toss the tomatoes, herbs and lime zest together in a bowl. Add the sunflower seeds and a squeeze of lime juice from one half. Season with salt and pepper.
When the sweet potatoes are nearly ready, heat a frying or griddle pan. Rub the steaks with 1 tsp oil each and season with salt and pepper. When the pan is nice and hot, add the steaks and fry for about 1-3 mins on each side or till done to your liking.
Pop the steaks on a board. Loosely cover with foil and leave to rest for 2-3 mins.
Toss the salad leaves with some salt, pepper and a squeeze of lime juice. Serve the steaks with the salad leaves and the sunflower seed salsa.