In a large sauté pan, heat olive oil on medium high heat for 2-3 minutes, then add garlic and allow to brown slightly. Add in lemon juice, maple syrup, currants, and all spices. Allow currants to cook for about 2 minutes on medium heat. Next, add rainbow chard and allow to reduce—5-7 minutes. When greens have wilted, remove from heat, set aside, and allow to cool.
When greens have cooled slightly, add cucumber, feta, and olives. Toss lightly, then transfer to bowl for serving. Prepare the rest of your board with the remaining ingredients.
On a bun, place 2 crispy fish fillets, tomato, cucumber, tapenade, Mediterranean greens, and tzatziki sauce and serve!