Cook the beet: Either add beet to a pot of water, bring to a boil, and cook until it's easy to insert a knife in the middle. Or wrap beet in aluminum foil and bake it in an oven preheated to 375 F. The cooking time takes around 40 minutes, depending on the size of the beet. Once cooked through, let cool before peeling.
While the beet is cooking, toast the pine nuts in a frying pan over medium heat for 2 minutes, or until lightly colored and fragrant. Remove from the heat and set aside to cool.
Also, cook the quinoa in a pot with the water or broth and a pinch of sea salt. Bring to a boil, then turn down the heat, cover, and simmer for 12 to 14 minutes, or until all of the water or broth is absorbed. Remove from the heat and keep covered for 5 more minutes. Transfer the quinoa to a bowl and fluff it with a fork; let cool.
Prepare the vinaigrette: In a small bowl, combine the sea salt and pepper with the lemon juice and oil, and whisk to emulsify. Stir in the herbs and set aside while peeling and chopping the beet.
Add the beet to the quinoa and toss gently. The quinoa will take on a nice pink color. Add the tomatoes, onion and cheese. Dress the salad with the vinaigrette and adjust the seasoning to your taste. Add more dressing if you like and serve with the pine nuts.