How to Make It
Prepare pasta according to package directions; drain and let cool completely, about 20 minutes. Place in a large bowl.
Stir together ranch dressing mix, vinegar, lemon zest and juice, honey, and salt in a small bowl. Slowly drizzle in olive oil in a steady stream, whisking constantly, until smooth and combined.
Add drained tuna, tomatoes, onion, and banana peppers to pasta in bowl. Drizzle in dressing; toss gently to coat. Add arugula; toss gently. Serve chilled or at room temperature.