Wash chard well in a large basin of cold water. Drain well. Cut or strip leaves from the stems. Slice stems into 1/4-inch pieces and set aside in a bowl. Roughly chop leaves and set aside in a second bowl.

Heat 2 teaspoons of the oil in a large skillet over medium high heat. Add onion and garlic and cook until the onions are soft and translucent, 5 to 7 minutes. Reduce heat if onions are cooking too fast. Add chard stems, cover and cook 2 minutes. Stir in chard leaves, cover and cook 3 to 5 minutes, stirring frequently. Add 1 tablespoon water, if necessary, to create enough steam to cook greens quickly. When ready, greens should be wilted but still bright green.

Meanwhile, arrange fillets in a single layer on a large plate and season with pepper. Squeeze lemon juice over the top, then drizzle on the tamari and sesame oil. Turn pieces over to coat all surfaces.

Heat remaining 2 teaspoons oil in a skillet over medium high heat. Add salmon, arranging pieces in a single layer, and cook 2 to 3 minutes on each side, or until done. When salmon is done, arrange it on top of the chard and serve immediately.