In a large ovenproof frying pan over med-high heat warm the oil.
Add the scallions and saute` for 1 min.
Add the garlic and tarragon, cook for 1 min.
Remove from heat.
In a medium bowl, combine eggs, beans, and milk.
Add onion mixture.
Pour the mixture into the frying pan.
Sprinkle with the chedder cheese and top with the asparagus in a pinwheel design.
Place over med-high heat and cook for 2 min.
Reduce heat to medium and cook for 5 min. or until the edges are set and the top is just slightly moist.
Place under the broiler about 3" from the heat and broil for 3 min., or until the frittata is puffed and slightly brown.