Preheat the oven to 400 °F (205 °C).
Prep salad ingredients per the instructions above. Place the spring mix in a bowl with cucumbers, tomatoes, and onion on top. Use a vegetable peeler to shave the carrot onto the top of the salad.
Whisk together ingredients for the vinaigrette and season with salt and pepper to taste.
Make the beans: Warm oil in a large saucepan over medium-low heat. Add onion and cook for 5 minutes, stirring frequently. Add garlic and thyme; cook for 1 minute, while stirring. Add beans and reserved liquid, tomatoes, broth, and salt and pepper. Increase heat to high and bring to a simmer. Reduce heat and simmer for 5 minutes to allow flavors to blend. Stir in additional broth, if needed, to thin the consistency.
Make the salmon: In a small bowl, whisk oil, mustard, lemon juice, salt, and pepper. Place salmon fillets, skin side down, in an 8-inch square baking dish. Spoon mustard glaze over fish. Bake for 8 minutes or to an internal temperature of 130 °F (55 °C) using a thermometer.
Toast the bread in a toaster oven.
Mix the lemon slices with the sparkling water. Serve over ice if desired.
Finish the salad: Dress with the vinaigrette.
Serve: Enjoy the salmon with beans, side salad, bread, and spritzer.