Creamy Corkscrew Salad with Tuna

1 pound Casarecce or other corkscrew pasta,
cooked to al dente (no pun intended)
340g can chunk light or white tuna, drained
2 oz old white cheddar, small dice
1/3 lb fresh green beans,
cooked to tender/crisp, cut into 1-inch long pieces
1/2 lb cherry or grape tomatoes, halved
(or strawberry tomatoes, cut into eighths)
2-3 green onions, finely sliced (green parts only)
1 1/4 cup light mayonnaise
2 tbs grainy Dijon mustard
kosher salt & fresh ground pepper, to taste

Whisk together mayonnaise, mustard, salt and pepper. In a large bowl, toss pasta together with dressing. Add green beans, onions and tomatoes and toss gently until evenly distributed. Refrigerate for an hour before serving to allow flavours to develop.

Note: If not serving the same day, keep tomatoes aside and add them as a garnish.