Heat oil in a large pot over medium heat. Add garlic, onions, and ginger. Saute until fragrant and translucent. Add tomatoes. Cover with a lid and cook until softened. See note 5 for an alternative cooking method.
Pour water followed by radish, and fish sauce. Simmer until radish is half done.
Add salmon, green chilies, and vegetables like okra and eggplant. Cook for 3 to 5 minutes. DO NOT STIR.
Sprinkle sinigang mix. Lightly stir to dissolve. Taste, add more sinigang mix if needed. Season with salt, to taste.
Add kangkong or your choice of leafy greens. Simmer for another minute and remove from heat. Serve with rice and enjoy!
Video
Notes
Salmon - use salmon belly, salmon head, fillet or even salmon trimmings.
Other souring agents (pangpa-asim) that can be used: calamansi, kamias, batwan, fresh tamarind.
Using fresh tamarind - wash unripe tamarind and place in a pot. Pour 1 cup water boil until soft and the skin begins to separate. Mash with a fork. Strain in a fine mesh over a bowl and continue to squeeze out the juices. Discard the skin and seeds. Pour the tamarind extract, step 4.
Leafy Vegetables - kangkong, sweet potato leaves, and bok choy/pak choi.
Alternative cooking method: simmering the ginger, onion, radish, and tomatoes in water. This should take about 5 minutes. Do steps 3 to 5.