Preheat oven to 350 degrees F. In a small bowl, combine the ricotta, basil, chives, garlic, two tablespoons of olive oil, salt and pep. Set aside.* Heat a grill or grill pan over medium-high heat. Brush the sliced squash with olive oil, salt and pep. Grill the sliced squash, flipping when grill marks appear and the squash has softened, about 3 minutes per side. Remove from heat and set aside.* Slice the bread down the middle and brush cut sides with olive oil. Place on baking sheet and warm in oven for 3 minutes. Remove from oven and spread ricotta mixture on all cut sides. Top the bottom bread slices with grilled squash and arugula then drizzle with balsamic glaze. Place top slices on top of arugula and place back in oven for 1 minute just to them warm through. Serve warm or at room temperature. *Can be made up to one day in advance.