Cook rice: Cook 1 cup dried rice with water, lime juice and salt.
Make Sauce: Melt butter in a small saucepan over medium heat. Cook garlic and pepper flakes until garlic starts to colour, about 1 minute. Add maple syrup, lime zest, lime juice and soy sauce. Cook until mixture boils. In a small bowl, stir together the cornstarch and water. Add to sauce and cook, stirring, until sauce thickens slightly, about 1 minute. Remove from heat and set aside.
Cook Salmon: Arrange salmon on a foil-lined baking sheet (for easy clean up). Season salmon with a bit of salt and pepper. Spread 1-2 tsp of the sauce over each fillet. Roast in preheated oven until just cooked through, about 12 minutes. Meanwhile, cook the spinach.
Cook Spinach: In a medium skillet, heat oil and sauce over medium heat. Add 1/2 of the spinach and sauté until just wilted. Remove from pan and set aside. Repeat with second 1/2 of spinach.
To serve: Divide rice among 4 bowls. Top each with 1/4 of the spinach and 1 salmon fillet, broken into large pieces. Drizzle with remaining sauce and sprinkle each with 1/2 teaspoon sesame seeds. Serve with a lime wedge for drizzling and any extra sauce (nice with the rice).