Heat the 1 tablespoon of olive oil in a skillet over medium-high heat. Add the garlic, onion and sausage, seasoning the meat with salt and pepper as desired. As you saute, break the sausage into small bite size pieces with your spoon.
In the meantime, boil water in a pot to cook the gnocchi according to package instructions (probably 2-3 minutes or until the pasta floats). Remove from the heat.
In a blender, blend together the basil (leaves only), 1/2 cup of water from the gnocchi pot, 1/2 cup olive oil and half and half.
Drain the gnocchi.
When the sausage is fully cooked, add the drained gnocchi and blender sauce to the skillet as well as the arugula and sundried tomatoes. Reduce heat to low and stir until the arugula wilts. Remove from heat and serve.