In a large bowl, toss peas, cabbage, radishes, green onions, parsley, and salt together.
In a large skillet over medium heat, cook bacon until crispy, 10 minutes. Using a slotted spoon, remove bacon from pan and place on a paper towel lined plate.
Return skillet to heat and add shallots and garlic. Cook until shallots are soft, 5 minutes. Add red wine, then whisk in mustard. Season with red pepper flakes, salt, and pepper.
Pour warm dressing over pea mixture and top with bacon and feta before serving.
