The day before, for the marinade, wash the orange and lime hot, dry and finely grate the peel. Halve the fruit and squeeze. Peel garlic and chop finely. Crush 1 tablespoon each of coriander and cumin seeds finely in a mortar. Mix the prepared ingredients, 1 tbsp. oregano and 1 tsp. pepper.
Wash the meat, dab dry and rub with the marinade all around. Place in a freezer bag, seal and chill overnight.
Preheat oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer). Brush roaster with oil. Remove meat from the freezer bag, season all around with salt. Place in the roaster and roast in the hot oven for approx. 2-2 1⁄2 hours. After approx. 1 1⁄2 hours pour on approx. 1⁄4 l water.
Remove the roast, wrap in foil and let it rest for about 10 minutes. Briefly roast tortillas one after the other in a pan without fat from each side. Cut the roast open. Put some salad on the tortillas and roll them up.