Cook the quinoa according to package instructions, typically by bringing it to a boil with twice the amount of water, then simmering until tender and the liquid is absorbed (about 15 minutes). Once cooked, spread the quinoa on a baking sheet or large plate and let it cool to room temperature for about 10-15 minutes. This prevents the warm quinoa from wilting the delicate herbs and cucumber later.
While the quinoa cools, prepare all your fresh components: peel and dice the cucumber into 1/2-inch pieces, cut the watermelon into 1-inch cubes, drain the pickled red onions on paper towels to remove excess liquid (this prevents the salad from becoming watery), and slice the fresh basil into thin ribbons (chiffonade). Keep the mint leaves whole for now—I like to add them at the very end so they stay bright and aromatic.
In a small bowl, whisk together the extra virgin olive oil, lime juice, and sea salt until emulsified. This creates a light, balanced dressing that won't overpower the refreshing fruit and vegetables. In a large serving bowl, combine the cooled quinoa from Step 1 with the watermelon, cucumber, pickled red onions, basil, and tofu feta from Step 2. Pour the dressing over the mixture.
Gently toss the salad until all ingredients are evenly coated with the dressing. Add the fresh mint leaves and give one more gentle toss to distribute them throughout. Drizzle the balsamic glaze over the top and scatter the toasted pumpkin seeds as a final garnish. I prefer to add the balsamic glaze just before serving so it doesn't get absorbed into the quinoa and keeps its glossy appearance.