This summer salad is ideal for a picnic. Just prepare, chill, and go.
In a large saucepan, heat oil over medium-high heat. Add thawed corn; cook until warmed through, 1 to 2 minutes.
Add spinach; cook until wilted, 1 to 2 minutes. Stir in tomatoes; cook until softened, 1 to 2 minutes.
Season with salt and pepper. Serve warm, cold, or at room temperature. (To chill, cool, then refrigerate, covered, for up to 4 hours.)