- Sort through the mung beans, discarding discolored or shriveled beans and any grit or dirt. Rinse beans in cold, running water until water runs clear. Drain well. 
- In a large pot, combine mung beans and water. Over medium heat, bring to a boil skimming froth that floats on top.  
- Lower heat, cover, and continue to cook for about 45 to 50 minutes or until beans have softened and skins have burst. Add more water as needed to maintain about 4 cups. 
- In another pot over medium heat, heat oil. Add onions and garlic and cook until tender and aromatic.  
- Add fish sauce and continue to cook for about 1 to 2 minutes. 
- Add cooked mung beans, including liquid. Bring to a boil.   
- Add ampalaya and cook for about 1 to 2 minutes or until tender yet crisp. 
- Add tinapa flakes and continue to cook until just heated through. 
- Season with salt and pepper to taste. 
- Add spinach, turn off heat and cover pot for about 1 to 2 minutes or until spinach is just wilted. Serve hot.