Place the okra into a large bowl and add the cumin, paprika, onion or garlic powder, and cayenne. Season with 1/2 teaspoon of salt and black pepper, drizzle in about 2 tablespoons of olive oil and toss to coat.
Heat a large skillet (frying pan) on medium high. When hot, add some of the okra, as much as will fit into a single layer and cook, undisturbed, until golden and slightly charred, about 2 minutes. Toss and cook for another 2 to 3 minutes until there is charring on the other sides. Transfer to a plate. Continue cooking the remaining okra.
Place the skillet back on medium high heat. Add the halloumi and cook until golden, 1 to 2 minutes. Flip over and cook the other side until golden, another minute or so. Transfer to a plate.
With the skillet still on medium high heat, add the corn and toss for 2 minutes, until it’s sweet and slightly charred.
In a bowl, add the yoghurt, garlic and season well with salt and black pepper. Stir until well combined.
To serve, spread most of the yoghurt onto a large serving plate or platter (save a couple tablespoons to drizzle on top). Scatter over the corn, followed by the okra and tomatoes. Tear up the halloumi and scatter on top along with the scallions. Drizzle the remaining yoghurt on top, and squeeze over some lime or lemon.