Tuna-pesto melts on rye with cos salad with candied walnuts and grapefruit

For the tuna melts:
1) Preheat the oven grill. In a medium bowl, combine the tuna, pesto, red peppers, mayonnaise and Parmesan. Mix well and season to taste with salt and black pepper.

2) Spoon tuna mixture onto the bread slices and place on a foil-lined baking tray. Top the tuna with slices of cheese. Grill for 2 minutes, until the cheese melts.

For the salad:
1) In a small bowl, whisk together the oil, vinegar and mustard and season to taste with salt and black pepper.

2) Arrange the lettuce on a serving plate and top with grapefruit segments and walnuts. Pour the dressing over the salad and serve.