Add 1 cup of dry quinoa and 2 cups of water to a saucepan. Cook on high until it starts boiling and then reduce to low heat. Simmer until all the water is evaporated. Remove from heat and fluff with a fork
.Set the grill to medium-high heat. Shuck the corn and spray it with cooking oil. Cook for 10 minutes and flip. Cook for an additional 10 minutes.
The peaches and zucchini take less time to cook. Cook the face down (sprayed with cooking oil) for 5 minutes on each side. Cut the grilled peaches and zucchini into sections. Hold the corn horizontal and cut in a downward motion to remove the kernels. Combine in a bowl with the quinoa, pepitas, and cut tomatoes.
To make the Sweet Basil Vinegarette: combine ingredients in a food processor or high-powered blender. Toss the vinegarette with the quinoa mixture. Serve on a bed of arugula.