Drain pineapple and save 1/4 cup of the juice.
In a blender or food processor, whirl the 1/4 cup pineapple juice, banana, ginger, chili, and lime juice until pureed. Scoop into a small bowl.
In a 10- to 12-inch nonstick frying pan over high heat, stir onion, bell pepper, and oil until vegetables are limp, 3 to 5 minutes. Add crushed pineapple and beans; stir just until hot, about 2 minutes. Cover and keep warm.
Rinse salmon and pat dry. Lay fish, skin down, on a sheet of foil. Trim foil to fit salmon.
Lay foil with salmon on a barbecue grill over a solid bed of hot coals or high heat on a gas grill (you can hold your hand at grill level only 2 to 3 seconds). Cook fish until opaque but moist-looking in center of thickest part (cut to test), 6 to 8 minutes.
Cut salmon into equal portions. Spoon bean mixture equally onto plates; top with salmon and ginger-banana sauce. Add lime juice from wedges and salt to taste.