Preheat the grill to high. Line an oven tray with foil. Finely chop the tomato and cucumber. Combine 2 tsp white vinegar and 1 tsp honey in a bowl and season with salt and pepper. Add the tomato and cucumber and stir to combine.
Step 2 — Prep fish
Combine the masala seasoning, half the yoghurt, 2 tsp oil and 1 tsp honey in a large bowl and season with salt and pepper. Add the fish and turn to coat.
Step 3 — Grill fish
Put the fish on the lined tray. Grill for 8 mins or until browned and cooked through.
Step 4 — Make coriander yoghurt
Meanwhile, pick the coriander leaves and finely chop the stems. Combine the coriander stems and remaining yoghurt in a small bowl and season with salt.
Step 5 — Warm tortillas
Heat a medium frypan over medium-high heat. Warm the tortillas, one at a time, for 30 secs each side or until heated through and slightly charred. Cover with a clean tea towel to keep warm. (Or, to heat in the microwave, put the tortillas on a plate, slightly overlapping, and microwave for 30 secs or until heated through.)
Step 6 — Get ready to serve
Flake the fish into large chunks. Divide the tortillas among plates and top with the fish and kachumber. Drizzle with the coriander yoghurt and scatter with the coriander leaves to serve.