In a large serving bowl, combine the fruit.
In a mason jar, mix together the vegetable oil, lemon juice, white wine vinegar, sugar, poppy seeds, Dijon mustard and salt. Put the lid on the jar and shake until mixed together. Store the dressing in an airtight container in the refrigerator for up to 1 week. Before serving, let the dressing stand to room temperature; whisk until blended.
Drizzle desired amount of dressing over the fruit, and gently toss to coat. Garnish with fresh mint if desired. Serve immediately.