Preheat the broiler to high.
Toast each bagel half in the toaster and then spread each evenly with cream cheese.
In a medium bowl, mix together the tuna, basil, lemon juice and yogurt. Season lightly with pepper.
Divide the tuna among the 4 bagel halves.
Top each bagel with cheddar cheese and 1-2 fresh tomato slices.
Drizzle lightly with olive oil and sprinkle with salt + pepper.
Place on a baking sheet and place in the oven.
Broil for 1-2 minutes or until the cheese has melted. Watch closely!
Top each melt with a few avocado slices and a handful of arugula. Eat!
