Prepare all vegetables by cutting them into wedges or bite-sized pieces.

In a large bowl, combine sweet potatoes, red bell pepper, red onions, and white onions.

Add rice vinegar, olive oil, red chili powder, cumin, coriander powders, and salt to the bowl. Toss well to coat the vegetables evenly.

Spread the seasoned vegetables on a large oven-proof tray.

Bake at 200°C (392°F) for 35-40 minutes, stirring halfway through for even roasting.

Monitor the vegetables after 30 minutes to prevent burning. Roast until they are well-roasted and slightly wrinkled.

Warm the whole wheat tortillas on a skillet or in a microwave.

To assemble the fajitas, place the roasted vegetables on a warmed tortilla.

Sprinkle with feta cheese, chopped fresh coriander, and torn iceberg lettuce leaves.

Drizzle with sour cream or hung yogurt.

Wrap the fajita and serve immediately.