Cook beet: Either add beet to pot of water, bring to a boil, and cook until it's easy to insert knife in 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 beet is cooking, toast pine nuts in frying pan over medium heat for 2 minutes, or until lightly colored and fragrant. Remove from heat and set aside to cool.
Cook quinoa in pot with water or broth and a pinch of sea salt. Bring to a boil, then turn down 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 with fork; let cool.
Prepare vinaigrette: In small bowl, combine sea salt and pepper with lemon juice and oil, and whisk to emulsify. Stir in herbs and set aside while peeling and chopping beet.
Add beet to quinoa and toss gently. Quinoa will take on a nice pink color. Add tomatoes, onion cheese. Dress salad with vinaigrette and adjust seasoning to taste. Add more dressing if you like and serve with pine nuts.