Cook lentils according to package directions. These really beef up as they cook, so don't underestimate one cup of the dried lentils. However, feel free to make more--you can always save for another meal. Once cooked, drain lentils and set aside.
Preheat oven to 400F. Meanwhile, marinate fish in white wine and lemon juice from the lemon. When the oven is heated, cook fish--it will take about 15 minutes, depending on how thick the fish fillets are. Cook to your own taste.
Heat 2 tbsp olive oil in a skillet over medium-high heat. Add the shallots and garlic and cook until softened, about 3 minutes. Add the spinach and cook, stirring frequently, until just wilted. Add the tomatoes, lentils, basil and parsley and stir. Cook until warmed through, about one minute. Add salt and pepper to taste; you can also add lemon juice at this point.
Serve by placing lentil mixture on a plate and putting fish on top.