Cook the rice according to the package directions.
Melt the butter in a large saucepan over medium-high heat. Add the garlic and cook for 1 minute.
Add the wine, tomatoes, and ¼ teaspoon each salt and pepper. Simmer for 3 minutes, until the sauce has thickened slightly.
Stir in the shrimp and simmer until cooked through, about 4 minutes.
Add the spinach and stir until wilted.
Spoon the rice into a serving dish or divide among plates. Top with the scampi and sprinkle with the tarragon.