Dice salmon into 1- x 1-inch pieces and pat dry. Spoon 2 Tbsp of TEMPURA BATTER MIX into a large bowl and toss salmon in it until each piece is coated. Whisk together the egg, the remainder of the TEMPURA BATTER MIX and the carbonated water.
Heat the oil in large pot over medium-high heat until it reaches 350°F. Dredge each piece of salmon through the batter, shake the the excess batter off and place about 6 pieces in the hot oil. Cook, stirring occasionally so the pieces don’t stick together, until batter is crispy and salmon is cooked through, 3-5 minutes. With a slotted spoon, scoop out the pieces and place on a paper towel lined plate. Immediately sprinkle with WEST COAST SALMON RUB. Repeat with the remainder of the salmon pieces.
Plate the salmon bites, and top with shallots and chives. Serve with TARTAR SAUCE and lemon wedges.