Dab the rump steak dry, cut the fat edge. Rub the steak with 2 tablespoons of fish sauce, season with pepper. Heat oil in a (grill) pan. Fry the steak in it over a high heat for approx. 1 minute, turn it over and fry it over medium heat for 2-3 minutes on each side.
Meanwhile clean the chilli, cut lengthwise, remove seeds, wash and finely chop. Peel garlic and chop finely as well. Mix 4 tablespoons fish sauce, lime juice, 2 tablespoons water and sugar. Stir in chilli and garlic.
Wash the herbs, dab dry and remove the leaves. Take the steak out of the pan and let it rest for a short time.
Wash the cucumber, peel it as desired and then cut it into slices. Wash and halve the tomatoes. Clean, wash and thinly slice the celery. Peel onion and cut into very thin slices or strips.
Cut steak into thin slices, mix with dressing and prepared salad ingredients. Sprinkle with herbs and garnish with lime wedges as desired.