Combine pineapple and sliced red pepper in a saute pan. Cook over medium heat until soft. Season tilapia with Old Bay (or similar seafood seasoning) - only lightly. Cook on the stove top or on the grill just until fish flakes.
Divide spinach over plates/bowls. Top with pineapple and pepper mixture. Let stand a few moments to allow the pineapple and bell pepper mixture to wilt the spinach. Add the tilapia. While pineapple pepper mixture is wilting spinach, cook white rice according to directions. Once prepared, add chopped scallions and let stand a few moments to blend flavors. Serve with finished tilapia.