Add canola oil and saute garlic, ginger, and green onion until fragrant and tender. Add the red pepper flakes. Mix the remaining ingredients in a separate bowl and add to the saucepan. Bring to a low simmer and cook for 10 minutes.
Preheat grill to medium-high heat.
Lightly season the salmon steaks with salt and pepper. Oil the grill with vegetable oil. Place the fish down for 4 to 5 minutes. Flip the fish over and brush with the barbecue sauce, continue cooking for another 4 to 5 minutes, until opaque throughout. Divide the baby spinach among 4 plates. Place the salmon steaks on top of the beds of spinach while still very hot. This will make the spinach wilt.