Combine the turkey, scallion, 1 tablespoon of the egg, the chile, garlic, cumin, and coriander. Season with salt and pepper. Leave to marinate for half an hour in the fridge.
Shape into 2 patties and broil or grill for 5 to 7 minutes on each side, till cooked through.
Preheat the oven to 400F. Place the tomatoes (cut side down), chiles and onion (cut side down) in a small baking pan; roast till just charred. When cooled, halve the chiles and scoop out the seeds. Place the chiles in a mortar and pound with a pestle or grind in a mini food processor. Add the garlic, sugar, and salt. Add the tomatoes and crush with a fork or pulse briefly until combined. Stir in the cilantro, lemon juice and onion; season with pepper. If your calorie budget allows, add the avocado.