Toss the steak, 1 chopped red pepper, 1 chopped red onion and 1 tbsp olive oil together in a large bowl, then cover with foil. Place in the fridge to marinade for at least half an hour.
Preheat your oven to 220C and line a baking tray. Toss the remaining red pepper ingredients together, then spread out on the tray evenly. Place in the oven to bake for 20-25 minutes, or until skins are charred, turning half-way through cooking.
Place in a blender, along with the juices and oils, and blitz completely smooth, adding a splash of water if needed to thin. Season to taste, then spoon into a dish and place in the fridge.
To make your kebabs, thread the refrigerated ingredients onto the wooden skewers. Brush the vegetables lightly with oil, then place on a grill or BBQ and cook until the steak is cooked according to your preference, turning the skewers as needed.