01 - Combine quinoa and water in a medium saucepan. Bring to a boil, then reduce heat to low, cover, and simmer for 12–15 minutes until water is absorbed and quinoa is fluffy. Remove from heat, fluff with a fork, and allow to cool completely.
02 - Preheat grill or grill pan to medium-high heat. Lightly brush watermelon wedges with oil. Grill for 2–3 minutes per side until distinct grill marks form and surface is slightly caramelized. Remove from heat and let cool, then cut into bite-sized cubes.
03 - In a large mixing bowl, whisk together olive oil, lime juice, balsamic vinegar, honey or maple syrup, sea salt, and black pepper until fully emulsified.
04 - Add cooled quinoa, grilled watermelon cubes, cucumber, red onion, mint, and parsley to the bowl with dressing. Gently toss until all ingredients are evenly coated.
05 - Transfer salad to a serving platter. Top with crumbled feta cheese and toasted pumpkin seeds or pistachios if using. Serve immediately or refrigerate and serve chilled.