Preheat your oven to 220°C (200°C fan) and position a rack in the middle. While the oven heats, line a large rimmed baking sheet with baking parchment. The paper makes cleanup almost effortless, and it prevents the chicken juices from sticking and burning onto the metal.

Slice the chicken and vegetables into even strips. Cut the chicken thighs into 2cm-wide strips – you'll feel the knife glide through the raw meat without resistance if your blade is sharp. Slice the peppers into similar-sized strips, discarding the white pith and seeds. Halve the red onions, then slice them into 1cm half-moons. The onions should separate naturally into ribbons as you cut.

Toss everything with the seasoning. In a large mixing bowl, combine the olive oil, smoked paprika, cumin, garlic powder, onion powder, cayenne (if using), salt and black pepper. Add the chicken strips, pepper strips and onion ribbons. Use your hands to massage the oil and spices into every piece – you'll smell the warm, earthy aroma of the paprika and cumin as they coat the ingredients. The chicken should look evenly brick-red, and the vegetables should glisten with oil.

Spread the mixture onto the baking sheet in a single layer. Arrange the chicken strips and vegetables so they're not overlapping. If they're crowded, they'll steam instead of roasting, and you'll miss that lovely charred edge. Leave a little space between each piece – you should hear a faint sizzle when the cold ingredients hit the hot tray.

Roast for 20-22 minutes, turning halfway. After 10 minutes, pull the tray out and use a spatula to flip the chicken strips and toss the vegetables. The peppers will have started to soften and wrinkle at the edges, and the chicken will look opaque on the bottom. Return to the oven and roast until the chicken is cooked through and the peppers have brown, blistered spots. A meat thermometer inserted into the thickest chicken strip should read 74°C. The kitchen will smell intensely of toasted cumin and smoky paprika.

Finish with lime juice and rest for 2 minutes. Squeeze the juice of one lime evenly over the hot tray. The acid brightens the spices instantly – you'll see the colour shift slightly as the juice hits the hot oil. Let the tray rest on the stovetop for two minutes. This allows the juices to redistribute so the chicken stays moist rather than drying out when you slice it.

Warm the tortillas and assemble the bowls. While the fajita mixture rests, warm the tortillas in a dry frying pan for 30 seconds per side, or directly over a gas flame for a few seconds until they puff slightly. To assemble, spoon a generous portion of the chicken, peppers and onions into each tortilla. Garnish with fresh coriander and serve with extra lime wedges on the side.