Heat oil in deep pot over medium heat.
Add onion and ginger to oil and sautee for two to three minutes.
Add garlic to pan and sautee for one more minute.
Add chicken to pan, and brown on both sides for five to seven minutes, stirring occasionally.
Add water, fish sauce, and bouillon cube and stir.
Bring to a boil.
If foam forms on top, skim it off with a spoon.
Reduce heat and cover pot.
Simmer for 30 - 35 minutes until chicken is cooked through.
Add papaya to pot and cook for about 5 minutes, or until crisp tender.
Add spinach to pot and submerge it into soup broth to allow it to wilt.