Bring a large saucepan of water to a boil over high heat. Add the rice noodles and cook until tender, about 5 minutes. Reserve 1 cup of the cooking water. Drain the noodles and rinse with warm water.
In a blender, combine the avocado, curry paste, lime juice, agave nectar, soy sauce and ½ cup of the cooking water. Puree until smooth, adding more cooking water as needed to form a smooth, pourable sauce.
Heat the olive oil in a large nonstick skillet set over medium heat. Add the onion and cook until tender, 4 to 5 minutes.
Add the garlic and ginger, and cook for 30 seconds.
Stir in the avocado curry sauce, shrimp and red bell pepper. Cook, stirring occasionally, until the shrimp are just cooked through and the peppers are tender, 3 to 4 minutes.
Add the rice noodles and toss to coat with the sauce.