Wash and slice chicken breasts into 1 1/2" slices.
In a small bowl, stir soy sauce, peanut butter, ginger, sesame oil and vinegar until well mixed. Stir in garlic and coriander.
Heat 3 Tablespoons of olive oil in a skillet over medium high heat. Add chicken to skillet and brown on both sides.
Remove chicken from pan, leaving any oil and juice in skillet.
Add onion and red pepper to skillet and stir fry for 3 minutes.
Return chicken to skillet and add peanut ginger sauce. Reduce heat to medium and cook for 2 minutes.
Add spinach to skillet. Combine well with other ingredients and cook for 1-2 minutes until heated through.
Place 1 cup of bean sprouts on plate and top with chicken and vegetable mixture. Serve immediately.