Cook each of the frozen vegetables following package instructions, drain.
Place green beans in a bowl, lima beans and artichoke hearts in another bowl, and the drained tuna in another bowl. Pour the dressing over the vegetables and the tuna. Allow the vegetables to cool completely, tossing occasionally. When cooled, cover all the bowls and place them in the fridge to chill.
When ready to prepare the salad, reserve some spinach leave. Tear the lettuce and remaining spinach into pieces, put the lettuce and spinach into a large salad bowl.
Line the edges of the bowl with the reserved spinach leaves, add the spring onion, green beans, and cheese.
Top with the lima beans, artichoke hearts, and tuna.
Serve with additional dressing as desired, and enjoy.