Slice baguette into about 15-20 baguette slices. Add olive oil to a small dish. Brush with olive oil on each side. Bake for 7 1/2 minutes, flip, and then bake for another 7 1/2 minutes.
Meanwhile, add feta to a food processor and blend quickly to break it down. Then add the cream cheese and blend until creamy.
Mix arugula with remaining olive oil in dish, add the juice from half a lemon and mix. Add about a 1/2 - 1 teaspoon of salt to taste to arugula and a few grinds of a pepper mill. Mix well.
When crostini are toasted, remove from oven and gently rub garlic on each slice of baguette. Vary garlic flavor by amount rubbed on crostini.
Top crostini with a layer of whipped feta and then a few sprigs of arugula.