Sinigang na Ulo ng Salmon (Salmon's Head in Tamarind-Soured Broth)

2 tbsp cooking oil
4 plum tomatoes, sliced
2 small red onions, sliced
thumb-sized piece of ginger, sliced and smashed
3 pcs siling labuyo (bird's eye chilis), chopped
4-5 pcs of tamarind broth cubes (or 1 packet of the powdered stuff)
1 1/2 liters water (I usually just eyeball it)
6 pcs siling mahaba/pansigang (long green chilis)
3/4 c daikon radish, sliced
3/4 c string beans, sliced into 1-inch pcs
1 salmon's head, chopped into 6-8 pieces
2 handfuls of kangkong (swamp cabbage) leaves

Saute the siling labuyo, tomatoes, and onions in oil. After a couple of minutes, melt the broth cubes in the mixture; add water and bring to a boil. Throw in the vegetables, except the kangkong, and bring to a boil again. Add the salmon pieces, cook covered until done. Add the kangkong leaves and remove from fire after 2 minutes.