Fuel up! Quinoa—technically a seed, not a grain—is one of very few plants that are complete proteins.
Bring vinegar to a light boil in a medium skillet over high heat. Reduce heat to medium-low and simmer until reduced to a syrupy consistency, about 10 minutes. (Watch carefully to avoid scorching.) Remove from heat; transfer to a small bowl.
Bring broth and ¼ teaspoon each salt and pepper to a boil in a medium saucepan over high heat; stir in quinoa. Cover, reduce heat to medium-low and cook until quinoa is tender and liquid is absorbed, 12 to 15 minutes.
Heat oil in a large nonstick skillet over medium-high heat. Add tomatoes and cook, stirring occasionally, until just starting to soften, about 2 minutes. Add kale and cook, stirring occasionally, until kale is almost wilted and tomatoes are softened, about 2 minutes. Sprinkle with remaining ¼ teaspoon each salt and pepper. Stir in cooked quinoa, sprinkle with almonds and goat cheese and top with avocado. Drizzle with balsamic reduction (you may have some left over; cover and keep for another use).