Put the chicken breasts in a 4-quart pan, add salt and water, and loosely cover. Bring to the boil then simmer gently for an hour.
Drain, saving the broth. Set the chicken aside to cool then chop into small pieces.
Add the oil to the same pot and sauté the bell peppers and onion until tender. Add the chicken to the pan and cook until warmed through.
Blend the tomatoes, chili powder, cumin, garlic, and oregano in a blender and add this mixture to the pan, as well as 2 cups of the broth. Bring to the boil, cover, and simmer for 15 minutes. Add salt to taste.
Heat the oil in a skillet and cook the tortillas one at a time until they are soft. This takes about 5 seconds per tortilla. Drain well. Strain the liquid from the chicken and put a tablespoon of chicken in the middle of each tortilla.
Roll the tortilla around the chicken to make a flute shape. Use toothpicks to hold the shape. Repeat with the rest of the tortillas and fry them in batches for a couple of minutes or until they hold their shape without the toothpicks.
Remove the toothpicks and serve three taquitos on each plate with guacamole for dipping.