In a large pot of boiling salted water, cook pasta according to package instructions; drain well.
Preheat oven to 400 degrees F.
In a small bowl, combine breadcrumbs, Italian seasoning, parmesan, and lemon zest. Set aside.
Melt butter in a sauté pan over medium heat. Add flour and whisk until lightly browned, about 1 minute.
Gradually whisk in milk, and stir until slightly thickened.
Add in seasonings - Dijon mustard, salt and pepper.
Remove from heat. Stir in cheddar cheese until smooth.
Stir in pasta, tuna and chopped artichoke hearts until well combined; transfer to a casserole dish sprayed with olive oil; sprinkle with breadcrumb mixture.
Place into oven and bake until golden brown and bubbly. about 25-30 minutes. Serve topped with tomato.