Tangy Shrimp and Spinach Salad

1 (6-oz) jar marinated artichoke hearts 

3-4 c. (about 5-oz) loosely packed spinach leaves (washed, stemmed, and torn) 

3/4 lb. fresh medium-sized shrimp (about 20), cooked, shelled, and devined 

8 medium mushrooms, halved lengthwise 

1 bunch green onions (about 8), coarsely chopped 

12 cherry tomatoes, halved 

1 T. red wine vinegar 

1 tsp. dry mustard 

1 tsp. tarragon 

Drain artichoke hearts, reserving 1/4 c. liquid. Combine artichoke hearts and next 5 ingredients in a large bowl. Combine artichoke liquid, vinegar, mustard, and tarragon, stirring until blended. Pour mixture over vegetables and shrimp, and toss lightly.