Preheat barbecue to high heat.
In a large spaghetti pot, heat virgin olive oil until smoking. Add garlic and Luganeya sausage and cook until garlic is medium light brown. Add collards and stir sausage through and allow to cook until liquid evaporates, about 8 to 10 minutes. Season with salt and pepper and set aside in warm place.
In a blender, place tarragon, vinegar, scallions and Dijon and blend until smooth. Leave blender on and drizzle in extra virgin olive oil to form a beautiful green emulsion. Pour into squirt bottle and set aside.
Remove skin and bone from monkfish and season well with salt and pepper. Brush lightly with oil and place skin side down on hottest part of barbecue. Cool 7 to 8 minutes on front side, flip and cook 4 to 7 minutes on other side, cooking through. Remove and slice into 1/2-inch slices. Divide collard mixture among 4 plates, place 2 or 3 slices of monkfish over greens and drizzle with tarragon vinaigrette.