Heat olive oil in a 10-inch (0.25-meter) skillet. Add yellow onion and sauté on medium high heat until onions are translucent. Add minced garlic and cook for 1 minute. Add nopales, Chili Colorado, dried shrimp and water. Bring to a boil. Cover and reduce heat to low, simmer for 10 minutes. Salt to taste. Finish with fresh cilantro before serving.