Place quinoa in large saucepan; add enough salted water to cover quinoa by 1 inch. Bring to boil. Reduce heat to medium-low; cover and simmer until quinoa is tender, 15 to 16 minutes. Drain. Chill until cool.
In an extra-large bowl, combine spinach leaves, garbanzos, cubed cucumber, halved tomatoes, mint leaves, and half of feta cheese. Add cooled quinoa and toss gently to blend.
In a small bowl, whisk vinegar and smoked paprika. Gradually whisk in oil. Season dressing with salt and pepper.
Pour dressing over salad; toss to coat. Season generously with salt and pepper. Sprinkle remaining feta.