In a saute pan, heat 1 tbsp of olive oil over medium high heat. Add half of the diced onion and cook, stirring occasionally until translucent and pale gold, about 10 minutes.
Add tomato sauce, paprika, 1 tbsp of cilantro and 1 tbsp of flour. Stir well, add the wine and 2 tbsp of fish stock, stir and bring to a boil.
Reduce to a simmer for 5 minutes.
Season with salt and pepper and set aside. Meanwhile, heat remaining 1 tbsp of olive oil to over medium high heat in a sauce pan. Add the remaining onion and cook, stirring occasionally for 5 minutes. Add the garlic and continue to cook for 3 minutes.
Reduce heat slightly and add poached Mahi Mahi, bread crumbs and remaining 2 tbsp of fish stock. Stir occasionally and cook for 5 minutes. Add egg yolk, stir gently and season with salt and pepper. Remove from heat and stir in remaining 1 tbsp cilantro. Let cool.
Lay peppers flat and place 2-3 tbsp of fish mixture down the length of the pepper. Roll the peppers and pinch closed. Refrigerate several hours until firm.
In a saute pan, pour canola oil to the depth of 1 ½”. Heat oil to 370°F. While oil heats one at a time, dip the stuffed peppers in beaten egg and dust in flour. Shake off excess flour. Place in the oil one at a time and fry for 3-4 minutes, until golden. Remove from oil and let drain on a paper towel. Repeat with remaining peppers.
Place tomato sauce mixture in a large frying pan over medium high heat. Add the peppers and simmer for 10 minutes, spooning sauce over the peppers. Garnish with additional breadcrumbs and cilantro. Serve.