Make ahead: In a medium-sized saucepan, bring the quinoa and water or stock to a boil. Cover, reduce heat to a low simmer for 15 minutes. Remove from heat and let it sit, covered, for 8 minutes. Fluff with a fork, place in a bowl, toss with 2 teaspoons of olive oil, let cool, and refrigerate
In a small jar, combine the red wine vinegar, lemon juice, honey, sea salt, black pepper, and extra virgin olive oil. Shake and set aside.
For the assembly, in a serving bowl, add the chilled quinoa, watermelon chunks and fresh chopped mint.
Pour about half of the dressing over the mixture and gently toss to coat. Taste and add more dressing if desired.
Top with crumbled feta and garnish with mint leaves.
Serve immediately.