Preparation:

Cut salmon into fillets, approximately 3 to 4 inches wide. Combine soy sauce, water, pineapple juice, garlic, and ginger to make soy marinade. Add salmon, and marinate in refrigerator, approximately 2 hours (time in refrigerator may be skipped if necessary).

Bring 3 cups water to boil in small saucepan. Add rice and reduce heat to simmer. Cover and simmer until water has been absorbed, approximately 20 minutes.

While rice is cooking, pour marinade into medium pot and bring to boil. Reduce heat and simmer. Preheat skillet to medium-high and lightly coat with cooking spray. Add salmon, cooking approximately 5 minutes each side. Remove salmon and set aside. In same skillet, add spinach and cook, stirring regularly. Spinach will lose 80 to 95 percent of volume. 

Once spinach is cooking, add flour to marinade and mix vigorously. Sauce will thicken. Add spinach to plate, cover with salmon, and drizzle sauce over both, discarding excess sauce. Serve rice on side.