Rinse the quinoa thoroughly under cold water using a fine-mesh strainer.
In a saucepan, combine the quinoa and water. Bring to a boil over high heat.
Reduce the heat to low, cover, and simmer for 10–15 minutes until the liquid is absorbed.
Remove from the heat and let the quinoa rest, covered, for 5 minutes. Fluff with a fork and allow it to cool.
Meanwhile, toast the sliced almonds in a dry skillet over medium heat for 3–6 minutes, stirring frequently until lightly golden and fragrant. Set aside.
In a small bowl or jar, whisk together the olive oil, lemon juice, diced shallots, Dijon mustard, honey, and salt until well combined.
In a large serving bowl, combine the cooled quinoa, arugula, sliced peaches, cucumber, red onion, goat cheese, toasted almonds, and chopped mint.
Pour the lemon-Dijon vinaigrette over the salad just before serving.
Toss gently until everything is evenly coated and serve immediately.